When it closed in 2013, it had been the United Kingdom's oldest operating prison, following the closure of HMP Lancaster Castle in 2011.

It was initially used by the British Army and later by American forces who constructed a new execution block to hang condemned prisoners.

It was also used for the storage of important historical documents from the Public Record Office in London, including the Domesday Book of 1086.

[7] During the Bloody Assizes following the Monmouth Rebellion at least 12 local men were held at the gaol before being hanged, drawn and quartered at the Market Cross.

[8][9] In 1773, a commissioner appointed by Parliament to inspect prisons around the country reported that sanitation at Shepton Mallet House of Correction was extremely poor.

Some are seen pining under diseases, expiring on the floors, in loathsome cells, of pestilential fevers, and the confluent smallpox.

Other prisoners were engaged in breaking stones which were used for roadbuilding, oakum picking (unpicking old ropes) and other tasks.

Boards are brought in and placed on the floor when the bedsteads are not sufficiently numerous.Ilchester Gaol closed in 1843, with the inmates being transferred to Shepton Mallet and Taunton.

[2] Notorious Bristol "baby farmer" Amelia Dyer spent six months at Shepton Mallet Prison.

Her trial was held at Long Ashton on 29 August 1879, and two newspapers report the summing-up of the judge, stating that she would reflect on her actions behind the walls of Shepton Mallet Gaol, for the period of six months under hard labour.

[22] At 10:15 pm on Saturday 2 July 1904 a fire, believed to have been started by a prisoner about half an hour earlier, was discovered in C block.

Whilst contemporary photographs show that the roof of C block was substantially destroyed, the building itself, being constructed of stone and concrete, remained nearly intact.

The names of the soldiers who died were Frank Girvan (of Fife), Glen Roy Williams (Bridgend) and Harold Smith (Manchester).

[45] With the outbreak of war the prison also took into protective storage many important historical documents from the Public Record Office in London, including the Domesday Book,[46][31] the logbooks of HMS Victory, the Olive Branch Petition (1775), and dispatches from the Battle of Waterloo.

[47] Some documents, but not Domesday Book, were moved out of Shepton Mallet on 5 July 1942 due to concern at the concentration of important items being held in one place, especially with German bombs falling on nearby Bath and Bristol.

[49] Between mid-1942 and September 1945 the prison was used by the American military as the "6833rd Guardhouse Overhead Detachment", later "The Headquarters 2912th Disciplinary Training Center – APO 508 United States Army".

Albert Pierrepoint is known to have disapproved of the Americans' practice of reading out to the condemned man as he stood on the trap-door the details of his offence and sentence, then allowing him to make a final statement.

Under British custom I was working to the sort of timing where the drop fell between eight and twenty seconds after I had entered the condemned's cell.

Executed prisoners interred there were not given coffins, but were put into cotton mattress covers and buried in individual graves under numbered markers.

Plot X had room for one hundred graves and was the first effort to segregate executed Army prisoners from those who had been killed in combat.

[94] In any case, all the grave markers in Plot E bear only numbers (not names), which makes identification of individual soldiers impossible without the key.

)[96] Amongst the soldiers held here were the Kray twins who, while serving out their national service in the gaol after absconding, met Charlie Richardson.

There were now about 260 prisoners who worked in a range of workshops, including plastic moulding, tailoring and scrap metal recovery.

Despite its ageing physical environment, the prison was a very safe place, with positive staff-prisoner relationships, a reasonable amount of activities, and a strong focus on addressing the serious risks posed by the population.

The closure ceremony was attended by officers and staff, past and present, the Bishop of Bath and Wells, veterans and serving personnel of MTC Colchester, representatives of the US Armed Forces and family and friends.

The event was also marked by a flypast of a Royal Naval Lynx helicopter from RNAS Yeovilton and an hour and a half peal from the local church bells.

The staff, who marched to parade just inside the main gates, accompanied by the RNAS Yeovilton Volunteer Band, were then dismissed.

The original deadline to declare a preferred bidder for the site was the end of March 2014 but this was put back until mid-August.

[119] Escapes, successful and attempted, from Shepton Mallet Prison include: HM Prison Shepton Mallet was featured as a haunted location on the American paranormal television series Paranormal Lockdown which first aired on 25 December 2018 on Destination America.

[145] In September 2020, Shepton Mallet Prison featured in the ITV three-part mini drama, Des, based on the 1983 arrest and trial of Scottish serial killer Dennis Nilsen, starring David Tennant and Daniel Mays.