The Quebec Agreement was a secret agreement between the United Kingdom and the United States outlining the terms for the coordinated development of the science and engineering related to
nuclear energy
Nuclear energy may refer to:
*Nuclear power, the use of sustained nuclear fission or nuclear fusion to generate heat and electricity
*Nuclear binding energy
Nuclear binding energy in experimental physics is the minimum energy that is required t ...
and specifically
nuclear weapon
A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or a combination of fission and fusion reactions ( thermonuclear bomb), producing a nuclear explosion. Both bom ...
s. It was signed by
Winston Churchill and
Franklin D. Roosevelt
Franklin Delano Roosevelt (; ; January 30, 1882April 12, 1945), often referred to by his initials FDR, was an American politician and attorney who served as the 32nd president of the United States from 1933 until his death in 1945. As the ...
on 19 August 1943, during
World War II
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposin ...
, at the
First Quebec Conference in Quebec City,
Quebec
Quebec ( ; )According to the Government of Canada, Canadian government, ''Québec'' (with the acute accent) is the official name in Canadian French and ''Quebec'' (without the accent) is the province's official name in Canadian English is ...
, Canada.
The Quebec Agreement stipulated that the US and UK would pool their resources to develop nuclear weapons, and that neither country would use them against the other, or against other countries without mutual consent, or pass information about them to other countries. It also gave the United States a veto over post-war British commercial or industrial uses of nuclear energy. The agreement merged the British
Tube Alloys
Tube Alloys was the research and development programme authorised by the United Kingdom, with participation from Canada, to develop nuclear weapons during the Second World War. Starting before the Manhattan Project in the United States, the Bri ...
project with the American
Manhattan Project
The Manhattan Project was a research and development undertaking during World War II that produced the first nuclear weapons. It was led by the United States with the support of the United Kingdom and Canada. From 1942 to 1946, the project w ...
, and created the Combined Policy Committee to control the joint project. Although Canada was not a signatory, the Agreement provided for a Canadian representative on the Combined Policy Committee in view of Canada's contribution to the effort.
British scientists performed important work as part of the
British contribution to the Manhattan Project
Britain contributed to the Manhattan Project by helping initiate the effort to build the first atomic bombs in the United States during World War II, and helped carry it through to completion in August 1945 by supplying crucial expertise. Follo ...
, and in July 1945 British permission required by the agreement was given for the use of nuclear weapons against Japan. The September 1944 Hyde Park Aide-Mémoire extended Anglo-American co-operation into the post-war period, but after the war ended, American enthusiasm for the alliance with Britain waned. The
McMahon Act (1946) ended technical co-operation through its control of "restricted data". On 7 January 1948, the Quebec Agreement was superseded by a ''
modus vivendi'', an agreement which allowed for limited sharing of technical information between the United States, Britain and Canada.
Background
Tube Alloys
The
neutron
The neutron is a subatomic particle, symbol or , which has a neutral (not positive or negative) charge, and a mass slightly greater than that of a proton. Protons and neutrons constitute the nuclei of atoms. Since protons and neutrons behav ...
was discovered by
James Chadwick
Sir James Chadwick, (20 October 1891 – 24 July 1974) was an English physicist who was awarded the 1935 Nobel Prize in Physics for his discovery of the neutron in 1932. In 1941, he wrote the final draft of the MAUD Report, which insp ...
at the
Cavendish Laboratory
The Cavendish Laboratory is the Department of Physics at the University of Cambridge, and is part of the School of Physical Sciences. The laboratory was opened in 1874 on the New Museums Site as a laboratory for experimental physics and is name ...
at the
University of Cambridge
, mottoeng = Literal: From here, light and sacred draughts.
Non literal: From this place, we gain enlightenment and precious knowledge.
, established =
, other_name = The Chancellor, Masters and Schola ...
in February 1932. In April 1932, his Cavendish colleagues
John Cockcroft
Sir John Douglas Cockcroft, (27 May 1897 – 18 September 1967) was a British physicist who shared with Ernest Walton the Nobel Prize in Physics in 1951 for splitting the atomic nucleus, and was instrumental in the development of nuclea ...
and
Ernest Walton
Ernest Thomas Sinton Walton (6 October 1903 – 25 June 1995) was an Irish physicist and Nobel laureate. He is best known for his work with John Cockcroft to construct one of the earliest types of particle accelerator, the Cockcroft–Walto ...
split
lithium
Lithium (from el, λίθος, lithos, lit=stone) is a chemical element with the symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard conditions, it is the least dense metal and the least dense solid ...
atoms with accelerated
protons. Then, in December 1938,
Otto Hahn
Otto Hahn (; 8 March 1879 – 28 July 1968) was a German chemist who was a pioneer in the fields of radioactivity and radiochemistry. He is referred to as the father of nuclear chemistry and father of nuclear fission. Hahn and Lise Meitner ...
and
Fritz Strassmann
Friedrich Wilhelm Strassmann (; 22 February 1902 – 22 April 1980) was a German chemist who, with Otto Hahn in December 1938, identified the element barium as a product of the bombardment of uranium with neutrons. Their observation was the key ...
at Hahn's laboratory in
Berlin-Dahlem
Dahlem ( or ) is a locality of the Steglitz-Zehlendorf borough in southwestern Berlin. Until Berlin's 2001 administrative reform it was a part of the former borough of Zehlendorf. It is located between the mansion settlements of Grunewald and ...
bombarded
uranium
Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weakly ...
with slowed neutrons, and discovered that
barium
Barium is a chemical element with the symbol Ba and atomic number 56. It is the fifth element in group 2 and is a soft, silvery alkaline earth metal. Because of its high chemical reactivity, barium is never found in nature as a free element.
...
had been produced. Hahn wrote to his colleague
Lise Meitner
Elise Meitner ( , ; 7 November 1878 – 27 October 1968) was an Austrian-Swedish physicist who was one of those responsible for the discovery of the element protactinium and nuclear fission. While working at the Kaiser Wilhelm Institute on ra ...
, who, with her nephew
Otto Frisch
Otto Robert Frisch FRS (1 October 1904 – 22 September 1979) was an Austrian-born British physicist who worked on nuclear physics. With Lise Meitner he advanced the first theoretical explanation of nuclear fission (coining the term) and first ...
, explained that the uranium
nucleus
Nucleus ( : nuclei) is a Latin word for the seed inside a fruit. It most often refers to:
*Atomic nucleus, the very dense central region of an atom
* Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA
Nucl ...
had been split. By analogy with the
division of biological cells, they named the process "
fission
Fission, a splitting of something into two or more parts, may refer to:
* Fission (biology), the division of a single entity into two or more parts and the regeneration of those parts into separate entities resembling the original
* Nuclear fissio ...
".

The discovery of fission raised the possibility that an extremely powerful
atomic bomb
A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or a combination of fission and fusion reactions ( thermonuclear bomb), producing a nuclear explosion. Both bomb ...
could be created. The term was already familiar to the British public through the writings of
H. G. Wells, in his 1913 novel ''
The World Set Free''. Sir
Henry Tizard
Sir Henry Thomas Tizard (23 August 1885 – 9 October 1959) was an English chemist, inventor and Rector of Imperial College, who developed the modern "octane rating" used to classify petrol, helped develop radar in World War II, and led the ...
's
Committee on the Scientific Survey of Air Defence
The Committee for the Scientific Survey of Air Defence (CSSAD), also known as the Tizard Committee after its chairman, Henry Tizard, was a pre-World War II scientific mission to study the needs of anti-aircraft warfare in the United Kingdom. The ...
was originally formed to study the needs of anti-aircraft warfare, but branched out to study air warfare generally. In May 1939, a few months before the outbreak of the
Second World War
World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the World War II by country, vast majority of the world's countries—including all of the great power ...
in Europe in September 1939, it was directed to conduct research into the feasibility of atomic bombs. Tizard tasked
George Paget Thomson, the professor of physics at
Imperial College London
Imperial College London (legally Imperial College of Science, Technology and Medicine) is a public research university in London, United Kingdom. Its history began with Prince Albert, consort of Queen Victoria, who developed his vision for a ...
, and
Mark Oliphant
Sir Marcus Laurence Elwin Oliphant, (8 October 1901 – 14 July 2000) was an Australian physicist and humanitarian who played an important role in the first experimental demonstration of nuclear fusion and in the development of nuclear weapon ...
, an Australian physicist at the
University of Birmingham
The University of Birmingham (informally Birmingham University) is a Public university, public research university located in Edgbaston, Birmingham, United Kingdom. It received its royal charter in 1900 as a successor to Queen's College, Birmingha ...
, with carrying out a series of experiments on uranium. By February 1940, Thomson's team had failed to create a chain reaction in natural uranium, and he had decided that it was not worth pursuing.
Oliphant's team reached a strikingly different conclusion. He had delegated the task to two German refugee scientists,
Rudolf Peierls
Sir Rudolf Ernst Peierls, (; ; 5 June 1907 – 19 September 1995) was a German-born British physicist who played a major role in Tube Alloys, Britain's nuclear weapon programme, as well as the subsequent Manhattan Project, the combined Allied ...
and Frisch, who could not work on the university's secret projects like
radar
Radar is a detection system that uses radio waves to determine the distance ('' ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, ships, spacecraft, guided missiles, motor vehicles, w ...
because they were
enemy alien
In customary international law, an enemy alien is any native, citizen, denizen or subject of any foreign nation or government with which a domestic nation or government is in conflict and who is liable to be apprehended, restrained, secured and ...
s, and therefore lacked the necessary security clearance. They calculated the
critical mass
In nuclear engineering, a critical mass is the smallest amount of fissile material needed for a sustained nuclear chain reaction. The critical mass of a fissionable material depends upon its nuclear properties (specifically, its nuclear fis ...
of a metallic sphere of pure
uranium-235
Uranium-235 (235U or U-235) is an Isotopes of uranium, isotope of uranium making up about 0.72% of natural uranium. Unlike the predominant isotope uranium-238, it is fissile, i.e., it can sustain a nuclear chain reaction. It is the only fissile ...
, and found that instead of tons, as everyone had assumed, as little as would suffice, and would explode with the power of thousands of tons of dynamite.
Oliphant took the
Frisch–Peierls memorandum to Tizard. As a result, the
MAUD Committee
The MAUD Committee was a British scientific working group formed during the Second World War. It was established to perform the research required to determine if an atomic bomb was feasible. The name MAUD came from a strange line in a telegram fro ...
was established to investigate further. It directed an intensive research effort. Four universities provided the locations where the experiments were taking place. The University of Birmingham undertook theoretical work, such as determining what size of critical mass was needed for an explosion. This group was run by Peierls, with the help of fellow German refugee scientist
Klaus Fuchs
Klaus Emil Julius Fuchs (29 December 1911 – 28 January 1988) was a German theoretical physicist and atomic spy who supplied information from the American, British and Canadian Manhattan Project to the Soviet Union during and shortly a ...
. The laboratories at the
University of Liverpool
, mottoeng = These days of peace foster learning
, established = 1881 – University College Liverpool1884 – affiliated to the federal Victoria Universityhttp://www.legislation.gov.uk/ukla/2004/4 University of Manchester Act 200 ...
and the
University of Oxford
The University of Oxford is a collegiate research university in Oxford, England. There is evidence of teaching as early as 1096, making it the oldest university in the English-speaking world and the world's second-oldest university in contin ...
experimented with different types of
isotope separation
Isotope separation is the process of concentrating specific isotopes of a chemical element by removing other isotopes. The use of the nuclides produced is varied. The largest variety is used in research (e.g. in chemistry where atoms of "marker" ...
. Chadwick's group at Liverpool dealt with
thermal diffusion Thermal diffusion may refer to:
* A thermal force on a gas due to a temperature gradient, also called ''thermal diffusion'' or Thermal transpiration.
** It is used to drive a gas pump with no moving parts called a Knudsen pump.
** It is the currentl ...
, a phenomenon observed in mixtures of mobile particles where the different particle types exhibit different responses to the force of a
temperature gradient
A temperature gradient is a physical quantity that describes in which direction and at what rate the temperature changes the most rapidly around a particular location. The temperature gradient is a dimensional quantity expressed in units of degre ...
.
Francis Simon's group at Oxford investigated the
gaseous diffusion
Gaseous diffusion is a technology used to produce enriched uranium by forcing gaseous uranium hexafluoride (UF6) through semipermeable membranes. This produces a slight separation between the molecules containing uranium-235 (235U) and uranium-2 ...
, which works on the principle that at differing pressures uranium 235 would diffuse through a barrier faster than uranium 238. This was determined to be the most promising method.
Egon Bretscher and
Norman Feather's group at Cambridge investigated whether another element, now called
plutonium
Plutonium is a radioactive chemical element with the symbol Pu and atomic number 94. It is an actinide metal of silvery-gray appearance that tarnishes when exposed to air, and forms a dull coating when oxidized. The element normally exhib ...
, could be used as a
fissile
In nuclear engineering, fissile material is material capable of sustaining a nuclear fission chain reaction. By definition, fissile material can sustain a chain reaction with neutrons of thermal energy. The predominant neutron energy may be typ ...
material. Because of the presence of a team of refugee French scientists led by
Hans von Halban
Hans Heinrich von Halban (24 January 1908 – 28 November 1964) was a French physicist, of Austrian-Jewish descent.
Family
He was descended on his father's side from Polish Jews, who left Kraków for Vienna in the 1850s. His grandfather, Heinr ...
, Oxford also had the world's main supply of
heavy water, which helped them theorise how uranium could be used for power.
In July 1941, the MAUD Committee produced two comprehensive reports that concluded that an atomic bomb was not only technically feasible, but could be produced before the war ended, perhaps in as little as two years. The MAUD Committee unanimously recommended pursuing its development as a matter of urgency, although it recognised that the resources required might be beyond those available to Britain. But even before its report was completed, the Prime Minister,
Winston Churchill, had been briefed on its findings by his scientific advisor,
Frederick Lindemann, and had decided on a course of action. A new directorate known by the deliberately misleading name of
Tube Alloys
Tube Alloys was the research and development programme authorised by the United Kingdom, with participation from Canada, to develop nuclear weapons during the Second World War. Starting before the Manhattan Project in the United States, the Bri ...
was created to co-ordinate this effort. Sir
John Anderson, the
Lord President of the Council, became the minister responsible, and
Wallace Akers from
Imperial Chemical Industries
Imperial Chemical Industries (ICI) was a British chemical company. It was, for much of its history, the largest manufacturer in Britain.
It was formed by the merger of four leading British chemical companies in 1926.
Its headquarters were at M ...
(ICI) was appointed its director.
Early American efforts
The prospect of Germany developing an atomic bomb was also of great concern to scientists in the United States, particularly those who were refugees from
Nazi Germany
Nazi Germany (lit. "National Socialist State"), ' (lit. "Nazi State") for short; also ' (lit. "National Socialist Germany") (officially known as the German Reich from 1933 until 1943, and the Greater German Reich from 1943 to 1945) was ...
and other
fascist
Fascism is a far-right, authoritarian, ultra-nationalist political ideology and movement,: "extreme militaristic nationalism, contempt for electoral democracy and political and cultural liberalism, a belief in natural social hierarchy and the ...
countries. In July 1939,
Leo Szilard
Leo Szilard (; hu, Szilárd Leó, pronounced ; born Leó Spitz; February 11, 1898 – May 30, 1964) was a Hungarian-German-American physicist and inventor. He conceived the nuclear chain reaction in 1933, patented the idea of a nuclear ...
and
Albert Einstein
Albert Einstein ( ; ; 14 March 1879 – 18 April 1955) was a German-born theoretical physicist, widely acknowledged to be one of the greatest and most influential physicists of all time. Einstein is best known for developing the theor ...
had
written a letter warning the President of the United States,
Franklin D. Roosevelt
Franklin Delano Roosevelt (; ; January 30, 1882April 12, 1945), often referred to by his initials FDR, was an American politician and attorney who served as the 32nd president of the United States from 1933 until his death in 1945. As the ...
, of the danger. In response, Roosevelt created an
Advisory Committee on Uranium
The S-1 Executive Committee laid the groundwork for the Manhattan Project by initiating and coordinating the early research efforts in the United States, and liaising with the Tube Alloys Project in Britain.
In the wake of the discovery of nuc ...
in October 1939, chaired by
Lyman Briggs of the
National Bureau of Standards
The National Institute of Standards and Technology (NIST) is an agency of the United States Department of Commerce whose mission is to promote American innovation and industrial competitiveness. NIST's activities are organized into physical sci ...
. Research concentrated on slow fission for power production, but with a growing interest in isotope separation. On 12 June 1940,
Vannevar Bush
Vannevar Bush ( ; March 11, 1890 – June 28, 1974) was an American engineer, inventor and science administrator, who during World War II headed the U.S. Office of Scientific Research and Development (OSRD), through which almost all wartim ...
, the president of the
Carnegie Institution of Washington
The Carnegie Institution of Washington (the organization's legal name), known also for public purposes as the Carnegie Institution for Science (CIS), is an organization in the United States established to fund and perform scientific research. Th ...
, and
Harry Hopkins
Harry Lloyd Hopkins (August 17, 1890 – January 29, 1946) was an American statesman, public administrator, and presidential advisor. A trusted deputy to President Franklin Delano Roosevelt, Hopkins directed New Deal relief programs before servi ...
, a key advisor to the president, went to the president with a proposal to create a
National Defense Research Committee
The National Defense Research Committee (NDRC) was an organization created "to coordinate, supervise, and conduct scientific research on the problems underlying the development, production, and use of mechanisms and devices of warfare" in the Un ...
(NDRC) to co-ordinate defence-related research. The NDRC was formally created on 27 June 1940, with Bush as its chairman. It absorbed the Advisory Committee on Uranium which had gone beyond its original role and was now directing research. It became the Uranium Committee of the NDRC.

One of Bush's first actions as the chairman of the NDRC was to arrange a clandestine meeting with
Air Commodore George Pirie, the British air attaché in
Washington, and
Brigadier
Brigadier is a military rank, the seniority of which depends on the country. In some countries, it is a senior rank above colonel, equivalent to a brigadier general or commodore, typically commanding a brigade of several thousand soldiers. In ...
Charles Lindemann, the British Army attaché (and Frederick Lindemann's brother), to discuss a British offer of a full exchange of technical information. Bush was strongly in favour of this proposal, and at their meeting on 8 July 1940, he offered advice on how it should be presented. It was endorsed at a
Cabinet
Cabinet or The Cabinet may refer to:
Furniture
* Cabinetry, a box-shaped piece of furniture with doors and/or drawers
* Display cabinet, a piece of furniture with one or more transparent glass sheets or transparent polycarbonate sheets
* Filing ...
meeting on 11 July, and an official acceptance was conveyed to
Lord Lothian, the
British Ambassador to the United States, on 29 July.
Among the wealth of information that the
Tizard Mission
The Tizard Mission, officially the British Technical and Scientific Mission, was a British delegation that visited the United States during WWII to obtain the industrial resources to exploit the military potential of the research and development ( ...
, a scientific mission sent to the United States to promote the exchange of military science and technology, brought to America were details about the MAUD Committee's deliberations and activities. Some information from the MAUD Committee had already been conveyed to the United States by
Ralph H. Fowler
Sir Ralph Howard Fowler (17 January 1889 – 28 July 1944) was a British physicist and astronomer.
Education
Fowler was born at Roydon, Essex, on 17 January 1889 to Howard Fowler, from Burnham, Somerset, and Frances Eva, daughter of George De ...
, the British scientific attaché to Canada. Cockcroft, a member of the Tizard Mission, brought more. Cockcroft and Fowler met with the Uranium Committee, but the information flow was largely one-way. Cockcroft reported that the American atomic bomb project lagged behind the British, and was not proceeding as fast. Work conducted in America included research by Szilard and
Enrico Fermi
Enrico Fermi (; 29 September 1901 – 28 November 1954) was an Italian (later naturalized American) physicist and the creator of the world's first nuclear reactor, the Chicago Pile-1. He has been called the "architect of the nuclear age" an ...
at
Columbia University
Columbia University (also known as Columbia, and officially as Columbia University in the City of New York) is a private research university in New York City. Established in 1754 as King's College on the grounds of Trinity Church in Manha ...
into the possibility of a controlled
nuclear chain reaction
In nuclear physics, a nuclear chain reaction occurs when one single nuclear reaction causes an average of one or more subsequent nuclear reactions, thus leading to the possibility of a self-propagating series of these reactions. The specific nu ...
; preliminary investigations into
isotope separation
Isotope separation is the process of concentrating specific isotopes of a chemical element by removing other isotopes. The use of the nuclides produced is varied. The largest variety is used in research (e.g. in chemistry where atoms of "marker" ...
using
centrifugation
Centrifugation is a mechanical process which involves the use of the centrifugal force to separate particles from a solution according to their size, shape, density, medium viscosity and rotor speed. The denser components of the mixture migrate ...
,
gaseous diffusion
Gaseous diffusion is a technology used to produce enriched uranium by forcing gaseous uranium hexafluoride (UF6) through semipermeable membranes. This produces a slight separation between the molecules containing uranium-235 (235U) and uranium-2 ...
and
thermal diffusion Thermal diffusion may refer to:
* A thermal force on a gas due to a temperature gradient, also called ''thermal diffusion'' or Thermal transpiration.
** It is used to drive a gas pump with no moving parts called a Knudsen pump.
** It is the currentl ...
processes; and efforts to produce plutonium in the
cyclotron
A cyclotron is a type of particle accelerator invented by Ernest O. Lawrence in 1929–1930 at the University of California, Berkeley, and patented in 1932. Lawrence, Ernest O. ''Method and apparatus for the acceleration of ions'', filed: J ...
at the
Radiation Laboratory
The Radiation Laboratory, commonly called the Rad Lab, was a microwave and radar research laboratory located at the Massachusetts Institute of Technology (MIT) in Cambridge, Massachusetts. It was first created in October 1940 and operated until 31 ...
at the
University of California
The University of California (UC) is a public land-grant research university system in the U.S. state of California. The system is composed of the campuses at Berkeley, Davis, Irvine, Los Angeles, Merced, Riverside, San Diego, San Fran ...
.
Kenneth Bainbridge
Kenneth Tompkins Bainbridge (July 27, 1904 – July 14, 1996) was an American physicist at Harvard University who did work on cyclotron research. His precise measurements of mass differences between nuclear isotopes allowed him to confirm Albert ...
from
Harvard University
Harvard University is a private Ivy League research university in Cambridge, Massachusetts. Founded in 1636 as Harvard College and named for its first benefactor, the Puritan clergyman John Harvard, it is the oldest institution of high ...
attended a MAUD Committee meeting on 9 April 1941, and was surprised to discover that the British were convinced that an atomic bomb was technically feasible. The Uranium Committee met at Harvard on 5 May, and Bainbridge presented his report. Bush engaged a group headed by
Arthur Compton
Arthur Holly Compton (September 10, 1892 – March 15, 1962) was an American physicist who won the Nobel Prize in Physics in 1927 for his 1923 discovery of the Compton effect, which demonstrated the particle nature of electromagnetic radia ...
, a
Nobel laureate in physics and chairman of the Department of Physics at the
University of Chicago
The University of Chicago (UChicago, Chicago, U of C, or UChi) is a private university, private research university in Chicago, Illinois. Its main campus is located in Chicago's Hyde Park, Chicago, Hyde Park neighborhood. The University of Chic ...
, to investigate further. Compton's report, issued on 17 May 1941, did not address the design or manufacture of a bomb in detail. Instead it endorsed a post-war project concentrating on atomic energy for power production. On 28 June 1941, Roosevelt created the
Office of Scientific Research and Development
The Office of Scientific Research and Development (OSRD) was an agency of the United States federal government created to coordinate scientific research for military purposes during World War II. Arrangements were made for its creation during May ...
(OSRD), with Bush as its director, personally responsible to the president. The new organisation subsumed the NDRC, now chaired by
James B. Conant, the
President of Harvard University
The president of Harvard University is the chief administrator of Harvard University and the ''ex officio'' president of the Harvard Corporation. Each is appointed by and is responsible to the other members of that body, who delegate to the pre ...
. The Uranium Committee became the Uranium Section of the OSRD, but was soon renamed the S-1 Section for security reasons.
Britain was at war, but the US was not. Oliphant flew to the United States in late August 1941, ostensibly to discuss the radar programme, but actually to find out why the United States was ignoring the MAUD Committee's findings. He discovered to his dismay that the reports and other documents sent directly to Briggs had not been shared with all members of the committee; Briggs had locked them in a safe. Oliphant then met with
William D. Coolidge, who was acting in Compton's place while the latter was in South America;
Samuel K. Allison, a colleague of Compton's at the University of Chicago;
Ernest O. Lawrence, the director of the Radiation Laboratory; Fermi and Conant to explain the urgency. In these meetings he spoke of an atomic bomb with forcefulness and certainty. Allison recalled that when Oliphant met with the S-1 Section, he "came to a meeting, and said 'bomb' in no uncertain terms. He told us we must concentrate every effort on the bomb and said we had no right to work on power plants or anything but the bomb. The bomb would cost $25 million, he said, and Britain did not have the money or the manpower, so it was up to us."
Bush and Conant received the final MAUD Report from Thomson on 3 October 1941. With this in hand, Bush met with Roosevelt and Vice-President
Henry A. Wallace
Henry Agard Wallace (October 7, 1888 – November 18, 1965) was an American politician, journalist, farmer, and businessman who served as the 33rd vice president of the United States, the 11th U.S. Secretary of Agriculture, and the 10th U.S. S ...
at the
White House
The White House is the official residence and workplace of the president of the United States. It is located at 1600 Pennsylvania Avenue Northwest, Washington, D.C., NW in Washington, D.C., and has been the residence of every U.S. preside ...
on 9 October 1941, and obtained a commitment to an expanded and expedited American atomic bomb project. Two days later, Roosevelt sent a letter to Churchill in which he proposed that they exchange views "in order that any extended efforts may be coordinated or even jointly conducted."
Collaboration
Roosevelt regarded this offer of a joint project as sufficiently important to have the letter personally delivered by
Frederick L. Hovde
Frederick Lawson Hovde (7 February 1908 – 1 March 1983) was an American chemical engineer, researcher, educator and president of Purdue University.
Born in Erie, Pennsylvania, Hovde received his Bachelor of Chemical Engineering from the Uni ...
, the head of the NDRC mission in London, but Churchill did not respond until December. He assured Roosevelt of his willingness to collaborate, and informed him that Hovde had discussed the matter with Sir John Anderson and Lord Cherwell, as Frederick Lindemann was now known. The
MAUD Committee
The MAUD Committee was a British scientific working group formed during the Second World War. It was established to perform the research required to determine if an atomic bomb was feasible. The name MAUD came from a strange line in a telegram fro ...
had considered the issue of collaboration with the United States, and had concluded that while pilot isotope separation plants could be established in the United Kingdom, full-scale production facilities would have to be built in the United States. The British expressed concerns about the security of the American project. Ironically, it was the British project that had already been penetrated by
atomic spies.
John Cairncross had given the
Soviet Union
The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a List of former transcontinental countries#Since 1700, transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, ...
a copy of the MAUD Committee report. Although not conveyed to the Americans, the British had other concerns about what might happen after the war if the Americans embraced
isolationism
Isolationism is a political philosophy advocating a national foreign policy that opposes involvement in the political affairs, and especially the wars, of other countries. Thus, isolationism fundamentally advocates neutrality and opposes entangle ...
, as had occurred after the
First World War
World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, the United States, and the Ottoman Empire, with fig ...
, and Britain had to fight the Soviet Union alone. The opportunity for a joint project was therefore missed. British and American exchange of information continued but their programmes remained separate.

The Japanese
attack on Pearl Harbor
The attack on Pearl HarborAlso known as the Battle of Pearl Harbor was a surprise military strike by the Imperial Japanese Navy Air Service upon the United States against the naval base at Pearl Harbor in Honolulu, Territory of Hawa ...
on 7 December 1941 led to the United States' entry into the war. Funding now became available in amounts undreamt of the year before. OSRD contracts were due to expire at the end of June 1942, and there was intense wartime competition for raw materials. It was agreed that in 1942–1943, the United States Army would fund $53 million of an $85 million programme. On 18 June 1942,
Colonel
Colonel (abbreviated as Col., Col or COL) is a senior military officer rank used in many countries. It is also used in some police forces and paramilitary organizations.
In the 17th, 18th and 19th centuries, a colonel was typically in charge ...
James C. Marshall was ordered to organise the Army component. He established his headquarters on the 18th floor of
270 Broadway
Tower 270 (also known as 270 Broadway, Arthur Levitt State Office Building, 80 Chambers Street, and 86 Chambers Street) is a 28-story mixed use building in the Civic Center and Tribeca neighborhoods of Manhattan, New York City. Completed in 1930 ...
in New York City, with the innocuous name of the
Manhattan Engineer District, following the usual practice of naming
engineer districts after the city in which its headquarters was located. The project soon adopted the name "Manhattan" as well. By September 1942, Bush and Conant felt that the time had come for the Army to take over, something already approved by the president on 17 June 1942, and
Brigadier General
Brigadier general or Brigade general is a military rank used in many countries. It is the lowest ranking general officer in some countries. The rank is usually above a colonel, and below a major general or divisional general. When appointed t ...
Leslie R. Groves, Jr.
Lieutenant General Leslie Richard Groves Jr. (17 August 1896 – 13 July 1970) was a United States Army Corps of Engineers officer who oversaw the construction of the Pentagon and directed the Manhattan Project, a top secret research project ...
became the director of the Manhattan Project on 23 September 1942. Groves attempted to tighten security through a policy of strict
compartmentalisation similar to the one that the British had imposed on radar.
The American effort soon overtook the British. British scientists who visited the United States in 1942 were astounded at the progress and momentum the Manhattan Project had assumed. On 30 July 1942, Anderson advised Churchill that: "We must face the fact that ...
urpioneering work ... is a dwindling asset and that, unless we capitalise it quickly, we shall be outstripped. We now have a real contribution to make to a 'merger'. Soon we shall have little or none". But Bush and Conant had already decided that British help was no longer needed. In October 1942, they convinced Roosevelt that the United States should independently develop the atomic bomb, despite the agreement of unrestricted scientific interchange between the US and Britain.
The positions of the two countries were the reverse of what they had been in 1941. American officials were concerned that Akers and other people from ICI involved in the Tube Alloys project were trying to exploit American nuclear scientific knowledge to create a profitable post-war industry. The
Secretary of War
The secretary of war was a member of the U.S. president's Cabinet, beginning with George Washington's administration. A similar position, called either "Secretary at War" or "Secretary of War", had been appointed to serve the Congress of the ...
,
Henry L. Stimson, felt that since the United States was doing "ninety percent of the work" on the bomb, it would be "better for us to go along for the present without sharing anything more than we could help". In December 1942, Roosevelt agreed to restricting the flow of information to what Britain could use during the war, even if doing so impeded the American project. The Americans stopped sharing any information on heavy water production, the
method of electromagnetic separation, the physical or chemical properties of plutonium, the details of atomic bomb design, or the facts about
fast neutron reactions. This adversely impacted the work of the
Montreal Laboratory
The Montreal Laboratory in Montreal, Quebec, Canada, was established by the National Research Council of Canada during World War II to undertake nuclear research in collaboration with the United Kingdom, and to absorb some of the scientists an ...
, the joint British and Canadian project that was investigating
nuclear reactor
A nuclear reactor is a device used to initiate and control a fission nuclear chain reaction or nuclear fusion reactions. Nuclear reactors are used at nuclear power plants for electricity generation and in nuclear marine propulsion. Heat from nu ...
design. In retaliation, the British stopped sending scientists to America, slowing the pace of work there, which had relied on British scientists. The Americans then ceased all information sharing.

The Tube Alloys Directorate considered whether Britain could produce a bomb without American help. A gaseous diffusion plant to produce 1 kg of
weapons-grade
Weapons-grade nuclear material is any fissionable nuclear material that is pure enough to make a nuclear weapon or has properties that make it particularly suitable for nuclear weapons use. Plutonium and uranium in grades normally used in nucl ...
uranium per day was estimated to cost up to £3 million in research and development, and anything up to £50 million to build in wartime Britain. A nuclear reactor to produce 1 kg of plutonium per day would have to be built in Canada. It would take up to five years to build and cost £5 million. The project would also require facilities for producing the required heavy water for the reactor costing between £5 million and £10 million, and for producing uranium metal, which would cost another £1.5 million. The project would need overwhelming priority, as it was estimated to require 20,000 workers, many of them highly skilled, 500,000 tons of steel, and 500,000 kW of electricity. Disruption to other wartime projects would be inevitable, and it was unlikely to be ready in time to affect the outcome of the
war in Europe. The unanimous response was that before embarking on this, another effort should be made to obtain American co-operation.
By March 1943 Bush and Conant had decided that British help would benefit some areas of the Manhattan Project. In particular, it could benefit enough from assistance from Chadwick and one or two other British scientists to warrant the risk of revealing weapon design secrets. Bush, Conant and Groves wanted Chadwick and Peierls to discuss bomb design with
Robert Oppenheimer
J. Robert Oppenheimer (; April 22, 1904 – February 18, 1967) was an American theoretical physicist. A professor of physics at the University of California, Berkeley, Oppenheimer was the wartime head of the Los Alamos Laboratory and is often ...
, and the construction company
Kellogg wanted British comments on the design of the
gaseous diffusion plant it was building.
Negotiations
Churchill took up the matter with Roosevelt when they met at the
Washington Conference on 25 May 1943. A meeting was arranged that afternoon between Cherwell and Bush in Hopkins's office in the White House, with Hopkins looking on. Both stated their respective positions, and Cherwell explained that Britain's post-war interest was in nuclear weapons, and not commercial opportunities. Hopkins reported back to Roosevelt, and Churchill and Roosevelt agreed that information interchange should be reviewed, and that the atomic bomb project should be a joint one. Hopkins sent Churchill a telegram confirming this on 17 June, but American policy did not change, largely because Roosevelt did not inform Bush when they next met on 24 June. When Churchill pressed for action in a telegram on 9 July, Hopkins counselled Roosevelt that "you made a firm commitment to Churchill in regard to this when he was here and there is nothing to do but go through with it."
Bush was in London on 15 July 1943 to attend a meeting of the British
War Cabinet
A war cabinet is a committee formed by a government in a time of war to efficiently and effectively conduct that war. It is usually a subset of the full executive cabinet of ministers, although it is quite common for a war cabinet to have senio ...
's Anti-U-Boat Committee. Sir
Stafford Cripps
Sir Richard Stafford Cripps (24 April 1889 – 21 April 1952) was a British Labour Party politician, barrister, and diplomat.
A wealthy lawyer by background, he first entered Parliament at a by-election in 1931, and was one of a handful of L ...
took him to see Churchill who told Bush that the President had given him his word of honour on full co-operation, and that he was incensed at obstruction by American bureaucrats. Bush suggested that he take up the matter with Stimson, who was also in London. Churchill did so on 17 July, and Stimson promised to submit the matter to Roosevelt. On 20 July, Roosevelt wrote to Bush with instructions to "renew, in an inclusive manner, the full exchange with the British Government regarding Tube Alloys", but since Bush was in London, he did not see this letter for another ten days. Stimson, Bush and Stimson's special assistant,
Harvey Bundy
Harvey Hollister Bundy Sr. (March 30, 1888 – October 7, 1963) was an American attorney who served as a special assistant to the Secretary of War during World War II. He was the father of William Bundy and McGeorge Bundy, who both served at high ...
, met Churchill, Cherwell and Anderson at
10 Downing Street in London on 22 July. None of them was aware that Roosevelt had already made his decision.
Stimson had just finished a series of arguments with the British about the need for an
invasion of France. He was reluctant to appear to disagree with them about everything, and, unlike Bush, sensitive to insinuations that Britain was being unfairly treated. He spoke in conciliatory terms about the need for good post-war relations between the two countries. For his part, Churchill disavowed interest in the commercial applications of nuclear technology. The reason for British concern about the post-war co-operation, they explained, was not commercial concerns, but so that Britain would have nuclear weapons after the war. Bush then proposed a five-point plan, which Stimson promised to put before the president for approval.
Anderson drafted an agreement for full interchange, which Churchill re-worded "in more majestic language". Anderson feared that Groves might tell Stimson and Bush that "like all Americans who come to our misty island, they have been taken in by our hypocritical cunning and carried away by our brilliant Prime Minister". When Conant found out about the agreement, he expressed the opinion that he would feel more at home on the staff of the ''
Chicago Tribune
The ''Chicago Tribune'' is a daily newspaper based in Chicago, Illinois, United States, owned by Tribune Publishing. Founded in 1847, and formerly self-styled as the "World's Greatest Newspaper" (a slogan for which WGN radio and television a ...
'', a newspaper renowned for its anti-British views. Anderson arrived in Washington with the draft on 5 August, and went over it with Conant and Bush. From the American point of view, nothing made it into the final draft that contradicted the existing policy on interchange of information. Anderson extracted one important concession: the creation of the Combined Policy Committee to oversee the joint project with representation from the United States, Britain and Canada. Conant's objections to Anderson's proposed arrangements for information interchange were met by assigning the task to the Combined Policy Committee. Stimson,
General
A general officer is an officer of high rank in the armies, and in some nations' air forces, space forces, and marines or naval infantry.
In some usages the term "general officer" refers to a rank above colonel."general, adj. and n.". O ...
George Marshall
George Catlett Marshall Jr. (December 31, 1880 – October 16, 1959) was an American army officer and statesman. He rose through the United States Army to become Chief of Staff of the US Army under Presidents Franklin D. Roosevelt and Harry ...
and
Rear Admiral
Rear admiral is a senior naval flag officer rank, equivalent to a major general and air vice marshal and above that of a commodore and captain, but below that of a vice admiral. It is regarded as a two star " admiral" rank. It is often rega ...
William R. Purnell reviewed the document and made minor changes, and it was then sent to the British Embassy for approval.
Agreement

A speedy drafting process was required because Roosevelt, Churchill and their political and military advisors converged for the
Quadrant Conference
The First Quebec Conference, codenamed "Quadrant", was a highly secret military conference held during World War II by the governments of the United Kingdom, Canada, and the United States. It took place in Quebec City on August 17–24, 1943, at ...
at the
Citadelle of Quebec
The Citadelle of Quebec (french: Citadelle de Québec), also known as ''La Citadelle'', is an active military installation and the secondary official residence of both the Canadian monarch and the governor general of Canada. It is located atop ...
on 17 August, hosted by the
Prime Minister of Canada
The prime minister of Canada (french: premier ministre du Canada, link=no) is the head of government of Canada. Under the Westminster system, the prime minister governs with the confidence of a majority the elected House of Commons; as suc ...
,
Mackenzie King
William Lyon Mackenzie King (December 17, 1874 – July 22, 1950) was a Canadian statesman and politician who served as the tenth prime minister of Canada for three non-consecutive terms from 1921 to 1926, 1926 to 1930, and 1935 to 1948. A L ...
. Most of the discussions were about the invasion of France. Although the Quebec Agreement was a bilateral one to which Canada was not a signatory, the British felt that Canada's contribution to Tube Alloys was significant enough that high-level representation was appropriate. King was therefore asked to nominate a Canadian member of the Combined Policy Committee, and he selected
C. D. Howe, the Canadian
Minister of Munitions and Supply
The Department of Munitions and Supply was the Canadian federal government ministry responsible for co-ordinating domestic industry during World War II. It was created by the ''Department of Munitions and Supply Act'' with C.D. Howe as its Minister ...
. Stimson, Bush and Conant would be the American members, while
Field Marshal
Field marshal (or field-marshal, abbreviated as FM) is the most senior military rank, ordinarily senior to the general officer ranks. Usually, it is the highest rank in an army and as such few persons are appointed to it. It is considered a ...
Sir
John Dill and Colonel
J. J. Llewellin would be the British members.
On 19 August Roosevelt and Churchill signed the Quebec Agreement, which was typed on four pages of Citadelle notepaper, and formally titled "Articles of Agreement governing collaboration between the authorities of the USA and UK in the matter of Tube Alloys". The United Kingdom and the United States agreed that "it is vital to our common safety in the present War to bring the Tube Alloys project to fruition at the earliest moment", and that this was best accomplished by pooling their resources. The Quebec Agreement stipulated that:
# The US and UK would pool their resources to develop nuclear weapons with a free exchange of information;
# Neither country would use them against the other;
# Neither country would use them against other countries without consent;
# Neither country would pass information about them to other countries without consent;
# That "in view of the heavy burden of production falling, upon the United States", the President might limit post-war British commercial or industrial uses of atomic energy.
The only part of the Quebec Agreement that troubled Stimson was the requirement for mutual consent before atomic bombs could be used. Had Congress known about it, they would never have supported it. The American veto over post-war British commercial and industrial uses made it clear that Britain was the junior partner in the
Grand Alliance. Churchill in particular considered the Quebec Agreement to be the best deal he could have struck under the circumstances, and the restrictions were the price he had to pay to obtain the technical information needed for a successful post-war nuclear weapons project.
Margaret Gowing
Margaret Mary Gowing (), (26 April 1921 – 7 November 1998) was an English historian. She was involved with the production of several volumes of the officially sponsored ''History of the Second World War'', but was better known for her books ...
noted that the "idea of the independent deterrent was already well entrenched."
The Quebec Agreement was a secret agreement. Its terms were known to but a few insiders, and its very existence was not revealed to the
United States Congress
The United States Congress is the legislature of the federal government of the United States. It is bicameral, composed of a lower body, the House of Representatives, and an upper body, the Senate. It meets in the U.S. Capitol in Washi ...
. The
Joint Committee on Atomic Energy The Joint Committee on Atomic Energy (JCAE) was a United States congressional committee that was tasked with exclusive jurisdiction over "all bills, resolutions, and other matters" related to civilian and military aspects of nuclear power from 1946 ...
was given an oral summary on 12 May 1947. On 12 February 1951, Churchill wrote to President
Harry S. Truman for permission to publish it, but Truman declined. Churchill therefore omitted it from his memoir, ''
Closing the Ring'' (1951). It remained a secret until Churchill read it out in the
House of Commons
The House of Commons is the name for the elected lower house of the bicameral parliaments of the United Kingdom and Canada. In both of these countries, the Commons holds much more legislative power than the nominally upper house of parliament. ...
on 5 April 1954. However, on 4 September 1943 the Soviet
atomic spy Ursula Kuczynski
Ursula Kuczynski (15 May 1907 – 7 July 2000), also known as Ruth Werner, Ursula Beurton and Ursula Hamburger, was a German Communist activist who spied for the Soviet Union during the 1930s and 1940s, most famously as the handler of nuclear sc ...
("Sonia") reported details of the agreement to the
GRU in Moscow, which she had probably obtained from Fuchs.
Implementation
Even before the Quebec Agreement was signed, Akers had already cabled London with instructions that Chadwick, Peierls, Oliphant and Simon should leave immediately for North America. They arrived on 19 August, the day it was signed, expecting to be able to talk to American scientists, but were unable to do so. Two weeks passed before American officials learned of the contents of the Quebec Agreement. Bush told Akers that his action was premature, and that the Combined Policy Committee would first have to agree on the rules governing the employment of British scientists. With nothing to do, the scientists returned to the UK. Groves briefed the OSRD
S-1 Executive Committee
The S-1 Executive Committee laid the groundwork for the Manhattan Project by initiating and coordinating the early research efforts in the United States, and liaising with the Tube Alloys Project in Britain.
In the wake of the discovery of nucl ...
, which had replaced the S-1 Committee on 19 June 1942, at a special meeting on 10 September 1943. The text of the Quebec Agreement was vague in places, with loopholes that Groves could exploit to enforce compartmentalisation. Negotiations on the terms of technical interchange dragged on until December 1943. The new procedures went into effect on 14 December with the approval of the Military Policy Committee (which governed the Manhattan Project) and the Combined Policy Committee. By this time British scientists had already commenced working in the United States.

Over the next two years, the Combined Policy Committee met only eight times. The first occasion was on the afternoon of 8 September 1943; Stimson discovered that he was the chairman only that morning. This first meeting established a Technical Subcommittee chaired by American
Major General
Major general (abbreviated MG, maj. gen. and similar) is a military rank used in many countries. It is derived from the older rank of sergeant major general. The disappearance of the "sergeant" in the title explains the apparent confusion of a ...
Wilhelm D. Styer. The Americans did not want Akers on the Technical Subcommittee due to his ICI background, so Llewellin nominated Chadwick, whom he also wanted to be Head of the British Mission to the Manhattan Project. The other members of the Technical Committee were
Richard C. Tolman
Richard Chace Tolman (March 4, 1881 – September 5, 1948) was an American mathematical physicist and physical chemist who made many contributions to statistical mechanics. He also made important contributions to theoretical cosmology in t ...
, who was Groves's scientific advisor, and
C. J. Mackenzie, the president of the Canadian
National Research Council. It was agreed that the Technical Committee could act without consulting the Combined Policy Committee whenever its decision was unanimous. It held its first meeting at
The Pentagon
The Pentagon is the headquarters building of the United States Department of Defense. It was constructed on an accelerated schedule during World War II. As a symbol of the U.S. military, the phrase ''The Pentagon'' is often used as a metonym ...
on 10 September 1943.
There remained the issue of co-operation between the Manhattan Project's
Metallurgical Laboratory
The Metallurgical Laboratory (or Met Lab) was a scientific laboratory at the University of Chicago that was established in February 1942 to study and use the newly discovered chemical element plutonium. It researched plutonium's chemistry and m ...
in Chicago and the Montreal Laboratory. At the Combined Policy Committee meeting on 17 February 1944, Chadwick pressed for resources to build a nuclear reactor at what is now known as the
Chalk River Laboratories
Chalk River Laboratories (french: Laboratoires de Chalk River; also known as CRL, Chalk River Labs and formerly Chalk River Nuclear Laboratories, CRNL) is a Canadian nuclear research facility in Deep River, about north-west of Ottawa.
CRL is a ...
. Britain and Canada agreed to pay the cost of this project, but the United States had to supply the heavy water. Because it was unlikely to have any impact on the war, Conant in particular was cool about the proposal, but heavy water reactors were still of great interest.
Groves was willing to support the effort and supply the heavy water required, but with certain restrictions. The Montreal Laboratory would have access to data from the Metallurgical Laboratory's research reactors at
Argonne and the
X-10 Graphite Reactor at Oak Ridge, but not from the production reactors at the
Hanford Site
The Hanford Site is a decommissioned nuclear production complex operated by the United States federal government on the Columbia River in Benton County in the U.S. state of Washington. The site has been known by many names, including SiteW ...
; nor would they be given any information about the chemistry of plutonium, or of methods for separating it from other elements. This arrangement was formally approved by the Combined Policy Committee meeting on 19 September 1944.
Chadwick supported the
British contribution to the Manhattan Project
Britain contributed to the Manhattan Project by helping initiate the effort to build the first atomic bombs in the United States during World War II, and helped carry it through to completion in August 1945 by supplying crucial expertise. Follo ...
to the fullest extent, abandoning any hopes of a British project during the war. With Churchill's backing, he attempted to ensure that every request from Groves for assistance was honoured. While the pace of research eased as the war entered its final phase, scientists were still in great demand, and it fell to Anderson, Cherwell and Sir
Edward Appleton, the
Permanent Secretary
A permanent secretary (also known as a principal secretary) is the most senior civil servant of a department or ministry charged with running the department or ministry's day-to-day activities. Permanent secretaries are the non-political civil s ...
of the
Department of Scientific and Industrial Research, which was responsible for Tube Alloys, to prise them away from the wartime projects in which they were invariably engaged. A British Mission led by Akers assisted in the development of gaseous diffusion technology in New York. Another, led by Oliphant, who acted as deputy director at the
Berkeley Radiation Laboratory
Lawrence Berkeley National Laboratory (LBNL), commonly referred to as the Berkeley Lab, is a United States national laboratory that is owned by, and conducts scientific research on behalf of, the United States Department of Energy. Located in ...
, assisted with the
electromagnetic separation process. As head of the British Mission to the
Los Alamos Laboratory
The Los Alamos Laboratory, also known as Project Y, was a secret laboratory established by the Manhattan Project and operated by the University of California during World War II. Its mission was to design and build the first atomic bombs. Rob ...
, Chadwick, and later Peierls, led a multinational team of distinguished scientists that included Sir
Geoffrey Taylor,
James Tuck,
Niels Bohr
Niels Henrik David Bohr (; 7 October 1885 – 18 November 1962) was a Danish physicist who made foundational contributions to understanding atomic structure and quantum theory, for which he received the Nobel Prize in Physics in 1922 ...
,
William Penney
William George Penney, Baron Penney, (24 June 19093 March 1991) was an English mathematician and professor of mathematical physics at the Imperial College London and later the rector of Imperial College London. He had a leading role in the d ...
, Frisch, and Fuchs. Four members of the British Mission became group leaders at Los Alamos. Penney observed the
bombing of Nagasaki
The United States detonated two atomic bombs over the Japanese cities of Hiroshima and Nagasaki on 6 and 9 August 1945, respectively. The two bombings killed between 129,000 and 226,000 people, most of whom were civilians, and remain the o ...
on 9 August 1945 and participated in the
Operation Crossroads
Operation Crossroads was a pair of nuclear weapon tests conducted by the United States at Bikini Atoll in mid-1946. They were the first nuclear weapon tests since Trinity in July 1945, and the first detonations of nuclear devices since the ...
nuclear tests in 1946.
A major strain on the Agreement came up in 1944, when it was revealed to the United States that the United Kingdom had made a secret agreement with
Hans von Halban
Hans Heinrich von Halban (24 January 1908 – 28 November 1964) was a French physicist, of Austrian-Jewish descent.
Family
He was descended on his father's side from Polish Jews, who left Kraków for Vienna in the 1850s. His grandfather, Heinr ...
to share nuclear information with France after the war in exchange for free use of patents related to nuclear reactors filed by French physicist
Frédéric Joliot-Curie
Jean Frédéric Joliot-Curie (; ; 19 March 1900 – 14 August 1958) was a French physicist and husband of Irène Joliot-Curie, with whom he was jointly awarded the Nobel Prize in Chemistry in 1935 for their discovery of Induced radioactivity. ...
and his
Collège de France
The Collège de France (), formerly known as the ''Collège Royal'' or as the ''Collège impérial'' founded in 1530 by François I, is a higher education and research establishment ('' grand établissement'') in France. It is located in Paris ...
team. Upon this revelation, the United States and Canada objected, stating that the Halban agreement violated the terms of the Quebec Agreement, namely the section about third-party information-sharing without prior mutual consent. The United Kingdom broke its obligations to France in order to satisfy the United States. Anderson was extremely concerned about alienating the French, and he and the
Secretary of State for Foreign Affairs
The secretary of state for foreign, Commonwealth and development affairs, known as the foreign secretary, is a minister of the Crown
Minister of the Crown is a formal constitutional term used in Commonwealth realms to describe a minister ...
,
Anthony Eden
Robert Anthony Eden, 1st Earl of Avon, (12 June 1897 – 14 January 1977) was a British Conservative Party politician who served as Prime Minister of the United Kingdom from 1955 until his resignation in 1957.
Achieving rapid pro ...
, suggested that the French be offered an undertaking that France would subsequently be included in the Manhattan Project, but Churchill did not agree, and remained adamantly opposed to any disclosures to France or the Soviet Union. After the war, the French government repudiated the Halban agreement.
The issue of patent rights was a complex one, and attempts to negotiate deals between Britain and the United States in 1942, and between Britain and Canada in 1943, had failed. After the Quebec Agreement was signed, British and American experts sat down together again and hammered out an agreement, which was endorsed by the Combined Policy Committee in September 1944. This agreement, which also covered Canada, was
retrospective
A retrospective (from Latin ''retrospectare'', "look back"), generally, is a look back at events that took place, or works that were produced, in the past. As a noun, ''retrospective'' has specific meanings in medicine, software development, popu ...
to the signing of the Quebec Agreement in August 1943, but owing to necessary secrecy, was not finalised until 1956, and covered all patents held in November 1955. Each of the three countries agreed to transfer to the others any rights it held in the others' countries, and waive any claims for compensation against them.
Llewellin returned to the United Kingdom at the end of 1943 and was replaced on the committee by Sir
Ronald Ian Campbell, the deputy head of the British Mission to the United States, who in turn was replaced by the British Ambassador to the United States,
Lord Halifax, in early 1945. Dill died in Washington on 4 November 1944, and was replaced both as Chief of the
British Joint Staff Mission and as a member of the Combined Policy Committee by Field Marshal Sir
Henry Maitland Wilson
Field Marshal Henry Maitland Wilson, 1st Baron Wilson, (5 September 1881 – 31 December 1964), also known as Jumbo Wilson, was a senior British Army officer of the 20th century. He saw active service in the Second Boer War and then during th ...
. It was therefore Wilson who, on 4 July 1945, under the clause of the Quebec Agreement that specified that nuclear weapons would not be used against another country without mutual consent, agreed that the use of nuclear weapons against Japan would be recorded as a decision of the Combined Policy Committee.
Hyde Park Aide-Mémoire

In September 1944, a second wartime conference was held in Quebec known as the
Octagon Conference
Princess Alice, Countess of Athlone">Princess Alice, and Clementine Churchill during the conference.
The Second Quebec Conference (codenamed "OCTAGON") was a high-level military conference held during World War II by the British and American g ...
. In the wake of a string of Allied victories, thoughts turned to post-war planning. Afterwards, Roosevelt and Churchill spent some time together at Roosevelt's
Springwood estate in
Hyde Park, New York
Hyde Park is a town in Dutchess County, New York, United States, bordering the Hudson River north of Poughkeepsie. Within the town are the hamlets of Hyde Park (CDP), New York, Hyde Park, East Park, Staatsburg, and Haviland, New York, Haviland. ...
. They discussed post-war collaboration on nuclear weapons, and on 19 September signed the Hyde Park Aide-Mémoire, detailing the agreement resulting from what they discussed. Most of this dealt with Bohr's thoughts on international control, but it also provided that "
ll collaboration between the United States and the British Government in developing Tube Alloys for military and commercial purposes should continue after the defeat of Japan unless and until terminated by joint agreement."
Of Roosevelt's advisors, only Hopkins and Admiral
William D. Leahy knew of this secret wartime agreement, and Leahy, possibly because he never believed that the atomic bomb would work, and was therefore perhaps not paying much attention, had only a muddled recollection of what had been said. When Wilson raised the Hyde Park Aide-Mémoire in a Combined Policy Committee meeting in June 1945, the American copy could not be found. The British sent Stimson a photocopy on 18 July. Even then, Groves questioned the document's authenticity until the American copy was located many years later in the papers of
Vice Admiral Wilson Brown, Jr., Roosevelt's naval aide, apparently misfiled in Roosevelt's Hyde Park papers by someone unaware of what Tube Alloys was, and who thought it had something to do with naval guns or boiler tubes.
End of the Quebec Agreement
Truman, who had succeeded Roosevelt on the latter's death on 12 April 1945,
Clement Attlee
Clement Richard Attlee, 1st Earl Attlee, (3 January 18838 October 1967) was a British politician who served as Prime Minister of the United Kingdom from 1945 to 1951 and Leader of the Labour Party from 1935 to 1955. He was Deputy Prime Min ...
, who had replaced Churchill as prime minister in July 1945, Anderson and
United States Secretary of State
The United States secretary of state is a member of the executive branch of the federal government of the United States and the head of the U.S. Department of State. The office holder is one of the highest ranking members of the president's ...
James F. Byrnes conferred while on a boat cruise on the
Potomac River
The Potomac River () drains the Mid-Atlantic (United States), Mid-Atlantic United States, flowing from the Potomac Highlands of West Virginia, Potomac Highlands into Chesapeake Bay. It is long,U.S. Geological Survey. National Hydrography Datas ...
, and agreed to revise the Quebec Agreement, with a view to replacing it with a looser form of co-operation on nuclear matters between the three governments. Groves, Secretary of War
Robert P. Patterson and Patterson's advisor
George L. Harrison met with a British delegation consisting of Anderson, Wilson,
Malcolm MacDonald, the
High Commissioner to Canada,
Roger Makins from the British Embassy in Washington, and
Denis Rickett
Sir Denis Hubert Fletcher Rickett, (27 July 1907 – 26 February 1997), was a British civil servant who served as Clement Attlee's Principal Private Secretary (PPS) from 1950 to 1951 and as vice-president of the World Bank from 1968 until 1 ...
, Anderson's assistant, on 15 November 1945 to draw up a communiqué. They agreed to retain the Combined Policy Committee. The Quebec Agreement's requirement for "mutual consent" before using nuclear weapons was replaced with one for "prior consultation", and there was to be "full and effective cooperation in the field of atomic energy", but in the longer Memorandum of Intention, signed by Groves and Anderson, this was only "in the field of basic scientific research". Patterson took the communiqué to the White House, where Truman and Attlee signed it on 16 November 1945. A draft agreement was approved by the Combined Policy Committee on 4 December 1945 as the basis for the revocation of the Quebec Agreement.

The next meeting of the Combined Policy Committee on 15 April 1946 produced no accord on collaboration, and resulted in an exchange of cables between Truman and Attlee. Truman cabled on 20 April that he did not see the communiqué he had signed as obligating the United States to assist Britain in designing, constructing and operating an atomic energy plant. Attlee's response on 6 June 1946 "did not mince words nor conceal his displeasure behind the nuances of diplomatic language." At issue was not just technical co-operation, which was fast disappearing, but the allocation of uranium ore. During the war this was of little concern, as Britain had not needed any ore, so all the production of the Congo mines and all the ore seized by the
Alsos Mission had gone to the United States, but now it was also required by the British atomic project. Chadwick and Groves reached an agreement by which ore would be shared equally.
The defection of
Igor Gouzenko
Igor Sergeyevich Gouzenko (russian: Игорь Сергеевич Гузенко ; January 26, 1919 – June 25, 1982) was a cipher clerk for the Soviet embassy to Canada in Ottawa, Ontario, and a lieutenant of the GRU (Main Intelligence Direc ...
and the resulting espionage conviction of
Alan Nunn May, a British physicist who had worked at the Montreal Laboratory, made it politically impossible for US officials to exchange information with the UK. Congress, unaware of the Hyde Park Aide-Mémoire because of the loss of the American copy, enacted the
McMahon Act. Signed by Truman on 1 August 1946, and in effect from midnight on 1 January 1947, this law ended technical co-operation. Its control of "restricted data" prevented the United States' allies from receiving any information. The remaining scientists were denied access to papers that they had written just days before. The McMahon Act fuelled resentment from British scientists and officials alike, and led directly to the British decision in January 1947 to develop its own nuclear weapons. In the United States, there was a furore over the British veto over the use of nuclear weapons when the Joint Committee on Atomic Energy was informed of the Quebec Agreement (but not the November 1945 agreement) on 12 May 1947, resulting in intense pressure on Truman to drop the provision. On 7 January 1948, Bush,
James Fisk, Cockcroft and Mackenzie concluded an agreement known as the ''
modus vivendi'', that allowed for limited sharing of technical information between the United States, Britain and Canada, which officially repealed the Quebec Agreement. Like the Quebec Agreement it replaced, the ''modus vivendi'' was classified "Top Secret".
As the
Cold War set in, enthusiasm in the United States for an alliance with Britain cooled as well. A September 1949 poll found that 72 per cent of Americans agreed that the United States should not "share our atomic energy secrets with England".
The reputation of the British was further tarnished by the 1950 revelation that Fuchs was a Soviet atomic spy.
British wartime participation in the Manhattan Project provided a substantial body of expertise that was crucial to the success of
High Explosive Research
High Explosive Research (HER) was the British project to develop atomic bombs independently after the Second World War. This decision was taken by a cabinet sub-committee on 8 January 1947, in response to apprehension of an American return ...
, the United Kingdom's post-war nuclear weapons programme, although it was not without important gaps, such as in the field of plutonium metallurgy. The development of the independent British nuclear deterrent led to the McMahon Act being amended in 1958, and to a resumption of the nuclear
Special Relationship
The Special Relationship is a term that is often used to describe the political, social, diplomatic, cultural, economic, legal, environmental, religious, military and historic relations between the United Kingdom and the United States or its ...
between America and Britain under the
1958 US–UK Mutual Defence Agreement.
Footnotes
Notes
References
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
*
External links
Quebec Agreement on Yale Law School siteHyde Park Aide-Mémoire on US State Department site
{{Portal bar, Canada, Politics, Nuclear technology, United Kingdom, United States, World War II
United Kingdom–United States treaties
World War II treaties
Treaties concluded in 1943
Secret treaties
Canada–United Kingdom relations
Canada–United States relations
Nuclear weapons policy
Nuclear history of the United Kingdom
History of the Manhattan Project
United Kingdom in World War II
August 1943 events
1943 in Canada
1943 in the United Kingdom
1943 in the United States
20th century in Quebec City
1940s in Quebec