Built in 1985 as a young offender institution, HMP Stocken opened as a category C closed training prison. It has since expanded with new accommodation being added in 1990, 1997, 1998, 2003, 2008, 2011 which has significantly expanded its roll. New workshops have been built as part of the prisoner accommodation expansion to ensure that Stocken is able to offer purposeful activity to all of the prisoners in its care. The prison is run by HMPS and the #1 governor is Michael Wood. The prison is part of the East Midlands Group.
Since its opening in 1985, with an operational capacity of 320, the prison has had several expansions, with new house blocks opening in 1990, 1997, 1998, 2002, 2007 ,2008 and 2011 which have increased its capacity to 1056. New workshops, including painting and decorating, bricks, Travis Perkins and a laundry, were built as part of the prisoner accommodation expansion.
In June 2015 there was a riot at Stocken, and part of the fabric of the prison was severely damaged. Riot at HMP Stocken 14/6/15. This has meant that K wing has been shut for refurbishment, reducing the number held at the prison to 672.
The accommodation is set out as:
- B, D and E wings: each comprised 66-bed single cellular accommodation with integral sanitation;
- G wing: 40-bed modular room accommodation for prisoners on the enhanced regime, with integral sanitation;
- H wing: 130-bed cellular accommodation with integral sanitation (five cells were doubles) for prisoners serving indeterminate sentences;
- I wing: 80-bed cellular accommodation with integral sanitation (eight rooms were doubles);
- J wing: 39-bed modular room accommodation; there was no integral sanitation but prisoners have 24-hour access to central bathroom facilities;
- K wing: 130-bed cellular accommodation with integral sanitation (five cells were doubles) including space for the integrated drug treatment system (IDTS); (current shut and being refurbished)
- L wing: 180-bed cellular accommodation with integral sanitation (20 cells were doubles) for prisoners on induction and on the enhanced regime;
- M wing: 180-bed cellular accommodation with integral sanitation (20 cells were doubles).
The number of prisoner held can be as high as 1056.