HMP Erlestoke was built on the former grounds of Erlestoke Manor House. The site was taken over 50 years ago as a detention centre and in1977 it became a young prisoners centre. The prison re-roled in 1988 as a category C adult male training prison and life-sentenced prisoners were first received in the 1990s. It has a focus on the rehabilitation of a longer-term population and is a national resource for high-intensity programmes on domestic violence, alcohol-related violence and substance abuse. HMP Erlestoke is run by HMPS as part of the South West Region. It has a capacity of 524 and the #1 governor is Chris Simpson.
- Marlborough unit 60-bed induction unit.
- Alfred unit 66-bed unit, general population
- Sarum unit 56-bed enhanced unit
- Wessex unit 68-bed unit, general population
- Imber unit 40-bed enhanced unit
- Avebury unit 40-bed enhanced unit.
- Kennet unit 40-bed enhanced unit,
- Silbury unit 124-bed interventions unit.
- Care & separation unit 9 bed