Portsdown Hill is a long
chalk
Chalk is a soft, white, porous, sedimentary carbonate rock. It is a form of limestone composed of the mineral calcite and originally formed deep under the sea by the compression of microscopic plankton that had settled to the sea floor. Cha ...
ridge in
Hampshire
Hampshire (, ; abbreviated to Hants) is a ceremonial county, ceremonial and non-metropolitan county, non-metropolitan counties of England, county in western South East England on the coast of the English Channel. Home to two major English citi ...
,
England
England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe ...
. The highest point of the hill lies within
Fort Southwick at 131m above sea level. The ridge offers good views to the south over
Portsmouth
Portsmouth ( ) is a port and city status in the United Kingdom, city in the ceremonial county of Hampshire in southern England. The city of Portsmouth has been a Unitary authorities of England, unitary authority since 1 April 1997 and is admi ...
, the
Solent
The Solent ( ) is a strait between the Isle of Wight and Great Britain. It is about long and varies in width between , although the Hurst Spit which projects into the Solent narrows the sea crossing between Hurst Castle and Colwell Bay ...
,
Hayling Island
Hayling Island is an island off the south coast of England, in the borough of Havant in the county of Hampshire, east of Portsmouth.
History
An Iron Age shrine in the north of Hayling Island was later developed into a Roman temple in the 1st c ...
and
Gosport
Gosport ( ) is a town and non-metropolitan borough on the south coast of Hampshire, South East England. At the 2011 Census, its population was 82,662. Gosport is situated on a peninsula on the western side of Portsmouth Harbour, opposite ...
, with the
Isle of Wight
The Isle of Wight ( ) is a Counties of England, county in the English Channel, off the coast of Hampshire, from which it is separated by the Solent. It is the List of islands of England#Largest islands, largest and List of islands of England#Mo ...
beyond. The hill is on the mainland, just to the north of
Ports Creek, which separates the mainland from
Portsea Island
Portsea Island is a flat and low-lying natural island in area, just off the southern coast of Hampshire in England. Portsea Island contains the majority of the city of Portsmouth.
Portsea Island has the third-largest population of all th ...
, on which lies the main part of the city of Portsmouth, one of the United Kingdom's main naval bases. To the north lies the
Forest of Bere, with the
South Downs
The South Downs are a range of chalk hills that extends for about across the south-eastern coastal counties of England from the Itchen valley of Hampshire in the west to Beachy Head, in the Eastbourne Downland Estate, East Sussex, in the ea ...
visible in the distance.
Butser Hill
Butser Hill is a hill and nature reserve in Hampshire, England. South-west of Petersfield, it is a biological and geological Site of Special Scientific Interest. It is a national nature reserve and a Special Area of Conservation. Part of it ...
can be seen on a clear day. The hill is formed from an
inlier
An inlier is an area of older rocks surrounded by younger rocks. Inliers are typically formed by the erosion of overlying younger rocks to reveal a limited exposure of the older underlying rocks. Faulting or folding may also contribute to the obs ...
of
chalk
Chalk is a soft, white, porous, sedimentary carbonate rock. It is a form of limestone composed of the mineral calcite and originally formed deep under the sea by the compression of microscopic plankton that had settled to the sea floor. Cha ...
which has been brought to the surface by an east–west
upfold of the local
strata
In geology and related fields, a stratum ( : strata) is a layer of rock or sediment characterized by certain lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by visible surfaces known as e ...
known as the
Portsdown Anticline.
Southwick House
Southwick House is a Grade II listed 19th-century manor house of the Southwick Estate in Hampshire, England, about north of Portsmouth. It is home to the Defence School of Policing and Guarding, and related military police capabilities.
Histor ...
is close by the north side of the hill, the HQ for U.S. General
Dwight D. Eisenhower
Dwight David "Ike" Eisenhower (born David Dwight Eisenhower; ; October 14, 1890 – March 28, 1969) was an American military officer and statesman who served as the 34th president of the United States from 1953 to 1961. During World War II, ...
during the
D-Day invasions; the generals prayed together before D-Day at Christ Church Portsdown, on the hill, which has a memorial window. The
A3(M) motorway
A controlled-access highway is a type of highway that has been designed for high-speed vehicular traffic, with all traffic flow—ingress and egress—regulated. Common English terms are freeway, motorway and expressway. Other similar terms ...
cuts through the east side of the hill while the original
A3 climbs over the centre by the
George Inn pub and Christ Church. The nearest railway stations (from west to east) are
Portchester
Portchester is a locality and suburb northwest of Portsmouth, England. It is part of the borough of Fareham in Hampshire. Once a small village, Portchester is now a busy part of the expanding conurbation between Portsmouth and Southampton o ...
,
Cosham
Cosham ( or ) is a northern suburb of Portsmouth lying within the city boundary but off Portsea Island. It is mentioned in the Domesday Book of 1086 along with Drayton and Wymering (mainland) and Bocheland ( Buckland), Frodington ( Fratton) and ...
and
Bedhampton
Bedhampton is a former village, and now suburb, located in the Borough of Havant, Hampshire, England. It is located at the northern end of Langstone Harbour and at the foot of the eastern end of Portsdown Hill.
Early mentions of Bedhampton ar ...
. There are many stories about real and imagined tunnels in the hill. The area contains active military research establishments, including one of the core sites of
Dstl
The Defence Science and Technology Laboratory (Dstl) is an executive agency of the Ministry of Defence of the United Kingdom. Its stated purpose is "to maximise the impact of science and technology for the defence and security of the UK". The a ...
(known as Dstl Portsdown West) and sites run by
QinetiQ. Part of the hill has been designated a
Site of Special Scientific Interest. Most of the southern flank of the ridge is designated as access land under the
Countryside and Rights of Way Act 2000
The Countryside and Rights of Way Act 2000 (c. 37), known informally as the CRoW Act or "Right to Roam" Act is a United Kingdom Act of Parliament affecting England and Wales which came into force on 30 November 2000.
Right to roam
The Act imp ...
and thereby freely available for the public to enjoy on foot.
During the early part of the
English Civil War
The English Civil War (1642–1651) was a series of civil wars and political machinations between Parliamentarians ("Roundheads") and Royalists led by Charles I ("Cavaliers"), mainly over the manner of Kingdom of England, England's governanc ...
Royalist forces from Portsmouth were involved in a number of skirmishes with Parliamentarians on the hill
In the Victorian era the hill was home to a fair on Easter Mondays.
Portsdown Forts
The forts on Portsdown Hill were built as a result of the
1859 Royal Commission, as part of a series of
fortifications built to defend Portsmouth and its
dockyard
A shipyard, also called a dockyard or boatyard, is a place where ships are built and repaired. These can be yachts, military vessels, cruise liners or other cargo or passenger ships. Dockyards are sometimes more associated with maintenance a ...
(which is 8 kilometres away) from a possible attack from ''inland'', as the development of rifled gun barrels made it possible for an invading army to land elsewhere, circle around to the top of the hill and bombard the city from there, rendering the existing
Hilsea Lines at the bottom of the ridge useless. A series of 6 forts were planned along the of the ridge. From west to east they are forts Fareham, Wallington, Nelson, Southwick, Widley and Purbrook. The line was finished off at the eastern end with Crookhorn Redoubt and Farlington Redoubt. The main threat was perceived to be from
Napoleon III
Napoleon III (Charles Louis Napoléon Bonaparte; 20 April 18089 January 1873) was the first President of France (as Louis-Napoléon Bonaparte) from 1848 to 1852 and the last monarch of France as Emperor of the French from 1852 to 1870. A neph ...
of
France
France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of overseas regions and territories in the Americas and the Atlantic, Pacific and Indian Oceans. Its metropolitan ar ...
, but this receded soon after the forts' completion. Due to this they became known as "Palmerston's Folly" but, though never needed for their original purpose, were useful
anti-aircraft
Anti-aircraft warfare, counter-air or air defence forces is the battlespace response to aerial warfare, defined by NATO as "all measures designed to nullify or reduce the effectiveness of hostile air action".AAP-6 It includes surface based, ...
gun emplacements 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 World War II by country, vast majority of the world's countries—including all of the great power ...
.
Fort Fareham
Fort Fareham is one of the Palmerston Forts, in Fareham, England. After the Gosport Advanced Line of Fort Brockhurst, Fort Elson, Fort Rowner, Fort Grange and Fort Gomer had been approved by the Royal Commission on the Defence of the United ...
is now a small industrial estate. The remains of the Fort are Grade II listed.
Fort Wallington has been largely demolished to make way for an industrial estate. What remains is now a Grade II
Listed Building
In the United Kingdom, a listed building or listed structure is one that has been placed on one of the four statutory lists maintained by Historic England in England, Historic Environment Scotland in Scotland, in Wales, and the Northern I ...
.
Fort Nelson has been extensively restored as an artillery museum run by the
Royal Armouries
The Royal Armouries is the United Kingdom's national collection of arms and armour. Originally an important part of England's military organization, it became the United Kingdom's oldest museum, originally housed in the Tower of London from t ...
. It is a Grade I Listed Building, the highest level of designation.
Fort Southwick was for many years an
Admiralty Research Establishment
The Admiralty Research Establishment (commonly known as ARE) was formed on 1 April 1984 from various Admiralty establishments. It became part of the Defence Research Agency on 1 April 1991.
Constituent parts on formation
* Admiralty Surface W ...
, sold in 2003 for housing. It is also now a Grade I Listed Building.
Fort Widley is owned by Portsmouth council, hosting a stable and various community rooms. Tours run on summer weekends. It is Grade II* Listed.
Fort Purbrook is open occasionally for craft fairs. It is also home to an activity centre which offers (but is not limited to) archery, rifle shooting and indoor rock-climbing. It is also Grade II* Listed. In October 2021, the fort was one of 142 sites across England to receive part of a £35-million injection into the government's
Culture Recovery Fund
The Culture Recovery Fund is a grants programme issued by the UK Government as a response to the COVID-19 pandemic. The fund aims to financially support cultural organisations in England (such as theatres, museums, and music venues) which had be ...
.
Guarding Fort Purbrook, the Crookhorn redoubt suffered from subsidence, and was demolished by 1876. The Farlington redoubt had only the ditches and gun positions dug, and was finally demolished in the 1970s. The tunnel between Crookhorn and Purbrook has been rediscovered.
Portsdown also gave its name to an army estate in Singapore. Long after the British army moved out (1967) the Portsdown estate continues to thrive, with Portsdown Road the main road running through the middle.
Fort Widley

Fort Purbrook
Fort Nelson
Portsdown SSSI
Over fifty hectares of the south face of the hill are a Site of Special Scientific Interest owing to its chalk grassland habitat. Grazing ceased in the early 1950s, and consequently the site was gradually invaded by scrub, mostly
hawthorn,
dogwood
''Cornus'' is a genus of about 30–60 species of woody plants in the family Cornaceae, commonly known as dogwoods, which can generally be distinguished by their blossoms, berries, and distinctive bark. Most are deciduous trees or shru ...
, and
wild privet
''Ligustrum vulgare'' (wild privet, also sometimes known as common privet or European privet) is a species of ''Ligustrum'' native to central and southern Europe, north Africa and southwestern Asia, from Ireland and southwestern Sweden south to M ...
. An intensive restoration programme funded by the
Countryside Commission
The Countryside Commission (formally the Countryside Commission for England and Wales, then the Countryside Commission for England) was a statutory body in England and Wales, and later in England only. Its forerunner, the National Parks Commissio ...
and
Portsmouth City Council
Portsmouth City Council is the local authority of the city of Portsmouth, Hampshire, England. It is a unitary authority, having the powers of a non-metropolitan county and district council combined. It provides a full range of local government s ...
was initiated in 1995; large areas of scrub have now been cleared by machine, and flowers and grasses allowed to regenerate naturally. Scrub re-encroachment is controlled by cattle and horses which graze overwinter.
Several species of butterfly became extinct owing to the loss of habitat to scrub, notably the
Adonis blue
The Adonis blue (''Lysandra bellargus'', also known as ''Polyommatus bellargus'') is a butterfly in the family Lycaenidae. It inhabits the Palearctic realm (Western Europe, Central Europe, Southern Europe, Southern Russia, Iraq, Iran, Caucasus, T ...
,
silver-studded blue
The silver-studded blue (''Plebejus argus'') is a butterfly in the family Lycaenidae. It has bright blue wings rimmed in black with white edges and silver spots on its hindwings, lending it the name of the silver-studded blue. ''P. argus'' can be ...
,
dingy skipper
The Dingy Skipper (''Erynnis tages'') is a butterfly of the family Hesperiidae.
Description
''Erynnis tages'' is different from other skippers because of the predominantly monochrome, gray-brown wing coloration and the marbling, which is only ...
, and
dark green fritillary. Others such as the
chalkhill blue
The chalkhill blue (''Lysandra coridon'') is a butterfly in the family Lycaenidae. It is a small butterfly that can be found throughout the Palearctic realm, where it occurs primarily in grasslands rich in chalk. Males have a pale blue colour, wh ...
and
small blue
The small blue (''Cupido minimus'') is a Palearctic butterfly in the family Lycaenidae. Despite its common name, it is not particularly blue. The male has some bluish suffusion at the base of its upper wings but is mostly dark brown like the fem ...
were at the brink of extinction, but are now flourishing again. Indeed, the hill has now probably the largest
metapopulation
A metapopulation consists of a group of spatially separated populations of the same species which interact at some level. The term metapopulation was coined by Richard Levins in 1969 to describe a model of population dynamics of insect pests in a ...
of the small blue in the UK.
References
External links
Palmerston Forts SocietyVictorian Forts data sheet on Fort PurbrookVictorian Forts data sheet on Fort WidleyVictorian Forts data sheet on Fort SouthwickVictorian Forts data sheet on Fort WallingtonVictorian Forts data sheet on Crookhorn RedoubtPortsdown TunnelsChrist Church PortsdownFort SouthwickFort WidleyThe Royal Armouries at Fort Nelson - Official Site
The Royal Armouries at Fort Nelson - GuideConservation Management and Volunteering on Portsdown Hill - the SSSI bit
{{DEFAULTSORT:Portsdown
History of Hampshire
Hills of Hampshire
Palmerston Forts
Napoleonic beacons in England