The stone gateway forming the north elevation of the gatehouse of the former Her Majesty's Prison Dorchester


Heritage Category:
Listed Building
List Entry Number:
Date first listed:
Date of most recent amendment:
Location Description:
North Square, Dorchester, West Dorset


Ordnance survey map of The stone gateway forming the north elevation of the gatehouse of the former Her Majesty's Prison Dorchester
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The building or site itself may lie within the boundary of more than one authority.

Location Description:
North Square, Dorchester, West Dorset
West Dorset (District Authority)
National Grid Reference:


A stone gateway originally built 1790-2 and designed by William Blackburn as part of his new prison for Dorchester, rebuilt onto the north front of a late-C19 prison gatehouse (only the north elevation of the prison gatehouse is listed).

Reasons for Designation

The stone gateway forming the north elevation of the gatehouse to the former HMP Dorchester is listed at Grade II for the following principal reasons:

* Architectural interest: with its high quality classical design and rustic stonework it forms the most prominent visual elements of HMP Dorchester; * Historic interest: it is the only surviving part of the original late-C18 prison designed by William Blackburn and is an interesting example of late-C19 architectural reuse; * Association: it is an interesting and relatively rare example of William Blackburn’s work, one of the most prolific architects of the late-C18 who played a crucial role in the C18 prison reform movement.


The former Her Majesty's Prison Dorchester occupies the site of the C12 castle. The castle buildings were lost when most of its stone was robbed for construction of a nearby friary in the early C14. The site lay largely vacant until the late C18. In 1787, the architect William Blackburn (1750 – 1790), was asked to examine the county prison in Dorchester located on the High Street. Blackburn was a prolific prison architect during his short career: he designed seventeen prisons and produced schemes or was asked for advice at five other sites. John Howard, the renowned prison reformist, described Blackburn as 'The ingenious Mr Blackburn… the only man capable of delineating my idea of what a prison ought to be’. Blackburn condemned the Dorchester facilities, as they did not allow inmates solitude to reflect on their crimes, and lacked ventilation and access to open spaces. He was asked to submit his own designs in 1788. Work on the new prison began in 1789 and was completed by 1794. The builder was John Fentiman of Newington Butts.

For the new gaol, Blackburn employed a courtyard plan, which consisted of a rectangular site with four, three-storey wings extending to the north and south from each corner of a central administration block and enclosing a number of courtyards. The whole site was surrounded by a tall rectangular boundary wall. A square gateway stood in the middle of the northern boundary wall. In the late C19, the prison was demolished and rebuilt. Building started circa 1879/ 80, and was completed by 1886. It was the first prison designed and built by the Prison Commissioners. The new prison provided accommodation for male and female prisoners, as well as a small number of cells for debtors. By 1956 the extent of the prison site had increased with the additions extending to the west. In the 1990s the kitchen, works department and gymnasium were built. Between 2007- 9 the cellblocks were refurbished, including the replacement of the cell windows and doors. In 2013, a new healthcare centre was added to the east side. The prison closed at the end of 2013.

The gateway, now forming the main entrance to the prison originating from the late C19, was originally built between 1790-2, and was designed by William Blackburn as part of the C18 prison. It formerly stood at the front of the central gaol lodge. Early drawings show that it originally included a set of double stud doors with a portcullis above. The parapet included an engraved stone reading ‘County Gaol’. Following the demolition of Blackburn’s prison in the late C19, the only above-ground remains which survived were the central part of the southern stretch of the perimeter wall, and the façade of the gatehouse with the attached gateway. The gatehouse was rebuilt in brick in the late C19 and its frontage was reformed from the C18 rusticated stone façade, resulting in the loss of at least part of the original C18 engraved parapet.


MATERIALS: rusticated ashlar limestone.

DESCRIPTION: the elevation has a central projecting bay with a large pair of double doors under a semi-circular arch constructed of large stone voussoirs. The rest of the façade is constructed of rusticated coursed stone blocks. There is a central string course, and another one above the arch. The whole elevation is topped by a plain stone parapet.


The contents of this record have been generated from a legacy data system.

Legacy System number:
Legacy System:


Brodie Allan, HMP Dorchester, revised 2013,
Dorset Historic Environment Record Monument Full Report: Dorchester Prison,
Wallsgrove J, Conservation and Development Plan for HMP Dorchester, 2013,


This building is listed under the Planning (Listed Buildings and Conservation Areas) Act 1990 as amended for its special architectural or historic interest.

The listed building(s) is/are shown coloured blue on the attached map. Pursuant to s.1 (5A) of the Planning (Listed Buildings and Conservation Areas) Act 1990 (‘the Act’), structures attached to or within the curtilage of the listed building (save those coloured blue on the map) are not to be treated as part of the listed building for the purposes of the Act.

End of official listing

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