The Sapperton Canal Tunnel is a tunnel on the

Thames and Severn Canal The Thames and Severn Canal is a canal in Gloucestershire in the south-west of England, which was completed in 1789. It was conceived as part of a cargo route from Bristol and the Midlands to London, linking England's two largest rivers for bet ...

near

Cirencester Cirencester ( , ; see #Pronunciation, below for more variations) is a market town and civil parish in the Cotswold District of Gloucestershire, England. Cirencester lies on the River Churn, a tributary of the River Thames. It is the List of ...

Gloucestershire Gloucestershire ( , ; abbreviated Glos.) is a Ceremonial counties of England, ceremonial county in South West England. It is bordered by Herefordshire to the north-west, Worcestershire to the north, Warwickshire to the north-east, Oxfordshire ...

, England. With a length of , it was the longest tunnel of any kind in England from 1789 to 1811. Construction, following an Act of Parliament, began in 1784. Twenty-six shafts were dug along the line of the tunnel and workfaces dug in each direction eventually joining up before the diameter of the tunnel was expanded. Difficulties were encountered related to

strata In geology and related fields, a stratum (: strata) is a layer of Rock (geology), rock or sediment characterized by certain Lithology, lithologic properties or attributes that distinguish it from adjacent layers from which it is separated by v ...

of Great Oolite (solid

limestone Limestone is a type of carbonate rock, carbonate sedimentary rock which is the main source of the material Lime (material), lime. It is composed mostly of the minerals calcite and aragonite, which are different Polymorphism (materials science) ...

) and

Fuller's Earth Fuller's earth is a term for various clays used as an absorbent, filter, or bleaching agent. Products labeled fuller's earth typically consist of palygorskite (also known as attapulgite) or bentonite. Primary modern uses include as absorbents ...

clay. These caused roof falls and narrowing of the channel which continued after the tunnel opened in 1789 and required frequent maintenance. The stone portals at either end are

listed building In the United Kingdom, a listed building is a structure of particular architectural or historic interest deserving of special protection. Such buildings are placed on one of the four statutory lists maintained by Historic England in England, Hi ...

s. Boats passed through by legging until 1911. The canal was abandoned by 1933 and subsequent roof falls mean that it is no longer navigable. Cotswold Canals Trust have proposed restoration.

History

The

was authorised by an Act of Parliament on 17 April 1783 but details of the tunnel had not been worked out, and arguments about its size continued for two to three months. Regular barges on the Severn were

trow A trow was a type of cargo boat found in the past on the rivers River Severn, Severn and River Wye, Wye in Great Britain and used to transport goods. Features The Mast (sailing), mast could be taken down so that the trow could go under bridg ...

s which were wide; those on the Thames were Thames

barge A barge is typically a flat-bottomed boat, flat-bottomed vessel which does not have its own means of mechanical propulsion. Original use was on inland waterways, while modern use is on both inland and ocean, marine water environments. The firs ...

s, wide. The only long tunnel in the country at the time was

Harecastle Tunnel Harecastle Tunnel is a canal tunnel on the Trent and Mersey Canal in Staffordshire between Kidsgrove and Tunstall. The tunnel, which is long, was once one of the longest in the country. Its industrial purpose was for the transport of coal to ...

, suitable for narrow boats just wide. A party of Commissioners from the Thames thought that the cost of a wide tunnel would be prohibitive, and that it should be built for narrow-beam boats, with the trows or barges unloading their cargos at each end of the tunnel. By late summer, the decision had been taken to build a broad tunnel, high and wide, and the company advertised for tunnellers in September. The tunnel would be long and below ground at its deepest point. It was expected to take four years to complete, beginning in early 1784. To speed the work, 26 shafts were sunk for many simultaneous workfaces, the deepest of which was . Small tunnels, known as headings, were dug in two different directions from the base of each shaft and the spoil lifted up the shaft and dumped in

Spoil tip A spoil tip (also called a boney pile, culm bank, gob pile, waste tip or bing) is a pile built of accumulated ''spoil'' – waste material removed during mining. Spoil tips are not formed of slag, but in some areas, such as England and Wales, ...

s above the route of the canal. A small temporary railway was later installed to take workers into the tunnel and remove waste materials. The use of explosives to expand the headings to the full size of the tunnel meant that acrid smoke and foul air built up. Chimneys were built in the shafts, with fires at their base to try to remove the foul air. The construction contract was awarded to Charles Jones, who managed to build about one third of it, but then had financial difficulties, and so other contractors were engaged to work on smaller sections. Difficulties during construction included different

. Great Oolite (solid

) has water permeable fissure which led to rock falls and spring formation and, during dry periods, the water leaking out of the canal. In areas where the tunnel went through

clay it had to be lined with brick. When the Fuller's Earth expanded this could lead to roof falls and pushed up the base of the tunnel reducing the depth of water for the boats passing through it. The tunnel was opened on 20 April 1789, after five years of construction. It has no

towpath A towpath is a road or trail on the bank of a river, canal, or other inland waterway. The purpose of a towpath is to allow a land vehicle, Working animal, beasts of burden, or a team of human pullers to tow a boat, often a barge. This mod ...

; boats were propelled through the tunnel by legging. There were some defects in the workmanship, causing closure for ten weeks' repairs after a year. Further attempts to repair and stabilise the walls included the insertion of oak beams at the base to stop the sides of the tunnel moving inwards as the clay expanded and, in 1904, a concrete lining to some sections. It was superseded as the longest canal tunnel in England in 1811 by the

Huddersfield Narrow Canal The Huddersfield Narrow Canal is an Navigability, inland waterway in northern England. It runs just under from Lock 1E at the rear of the University of Huddersfield campus, near Aspley, West Yorkshire, Aspley Basin in Huddersfield, to the ju ...

's Standedge Tunnel, at long, afterwards lengthened, that remains the highest, longest and deepest instance in

Britain Britain most often refers to: * Great Britain, a large island comprising the countries of England, Scotland and Wales * The United Kingdom of Great Britain and Northern Ireland, a sovereign state in Europe comprising Great Britain and the north-eas ...

– which only accommodates . Strood Tunnel on the Thames and Medway Canal was when it opened in 1824, but was interrupted six years later by a short section to create a passing basin. The last commercial traffic passed through the tunnel in 1911 and in 1916 further roof falls occurred. The whole canal was abandoned by 1933. The tunnel was passable until at least 1966, but is now blocked by roof collapses over several hundred yards, mainly in sections where the ground is

fuller's earth Fuller's earth is a term for various clays used as an absorbent, filter, or bleaching agent. Products labeled fuller's earth typically consist of palygorskite (also known as attapulgite) or bentonite. Primary modern uses include as absorbents ...

. Restoration is proposed by the Cotswold Canals Trust as part of their project to re-open a direct route between Thames and Severn. The trust has operated

tourist Tourism is travel for pleasure, and the commercial activity of providing and supporting such travel. UN Tourism defines tourism more generally, in terms which go "beyond the common perception of tourism as being limited to holiday activity on ...

boat trips into the tunnel in winter months. The

Sapperton railway tunnel The Sapperton Railway Tunnel is a railway tunnel near Sapperton, Gloucestershire in the United Kingdom. It carries the Golden Valley Line from Stroud to Swindon through the Cotswold escarpment. It was begun by the Cheltenham and Great Wester ...

, on the

Golden Valley Line The Golden Valley line is the popular name for the railway line connecting , , and in England. Originally constructed as the Cheltenham and Great Western Union Railway, the line opened between Swindon and Kemble (with a branch to Cirencest ...

, follows a similar route under the '

Cotswold Edge The Cotswolds ( ) is a region of central South West England, along a range of rolling hills that rise from the meadows of the upper River Thames to an escarpment above the Severn Valley and the Vale of Evesham. The area is defined by the bedro ...

'. There have been proposals to pump water from the

River Severn The River Severn (, ), at long, is the longest river in Great Britain. It is also the river with the most voluminous flow of water by far in all of England and Wales, with an average flow rate of at Apperley, Gloucestershire. It rises in t ...

toward the periodically water-stressed

Thames Basin The River Thames ( ), known alternatively in parts as the River Isis, is a river that flows through southern England including London. At , it is the longest river entirely in England and the second-longest in the United Kingdom, after the ...

; if so the tunnel and canal eastward could be used for this.

Portals

The northern portal near Sapperton village was built between 1784 and 1789 by Josiah Clowes. It was restored in 1996. The southern Coates portal was built by the engineer Robert Whitworth and has doric columns and vermiculated masonry. It was restored in 1980.

In fiction

In '' Hornblower and the Atropos'' by C.S. Forester, Hornblower helps the boatman "

leg A leg is a weight-bearing and locomotive anatomical structure, usually having a columnar shape. During locomotion, legs function as "extensible struts". The combination of movements at all joints can be modeled as a single, linear element cap ...

" through Sapperton Tunnel after the boatman's assistant is incapacitated. Forester spends the first two chapters of the book on the canal-boat journey, Roughly a third of the first chapter is devoted to the tunnel. In the novel '' Gone'' by

Mo Hayder Beatrice Clare Dunkel (born Clare Damaris Bastin; pen names, Mo Hayder and Theo Clare; 2 January 1962 – 27 July 2021) was a British author. Earlier in her life she worked as an actress and model under the name Candy Davis and appeared as Miss B ...

the tunnel is used extensively as a location in this crime thriller. An episode of

Midsomer Murders ''Midsomer Murders'' is a British Mystery fiction, mystery television series, adapted by Anthony Horowitz and Douglas Watkinson from the novels in the ''Chief Inspector Barnaby'' book series created by Caroline Graham (writer), Caroline Graham. ...

titled ''The Green Man'' (series 7 episode 1) was partly filmed at the tunnel. The tunnel plays a significant part in ''Slaughter in the Sapperton Tunnel'' by Edward Marston. ISBN 978-0-7490-2681-3

Coordinates

References

Bibliography

* * * * * *

External links

Current state of the tunnel and restoration plans Stroud Voices (Canal tunnel selection) - oral history site
* {{s-end Canal tunnels in England Canals in Gloucestershire Tunnels completed in 1789 Tunnels in Gloucestershire 1789 establishments in England Disused tunnels Thames and Severn Canal