Crowding levels are set and managed carefully by the National Offender Management Service. Prison crowding occurs when the number of prisoners in an accommodation unit exceeds the certified normal capacity (CNA) of that unit. A prison’s “certified normal accommodation” (CNA) is therefore its agreed capacity when there is no crowding. A prison’s “operational capacity” is the maximum number of prisoners it is allowed to hold over and above CNA taking into account control, security and the proper operation of regimes. In addition operational managers must ensure that each cell used for the confinement of prisoners has sufficient heating, lighting and ventilation and is of adequate size for the number of prisoners to be held in it. Operational capacity in prisons is set by Directors of Offender Management on behalf of the Secretary of State in both publicly managed and contracted establishments.
The Government are committed to increasing substantially the capacity of the prison estate and plans to provide 96,000 places by 2014.
On 27 April 2009 the Justice Secretary announced that the Ministry of Justice plans to build up to five new 1,500 place prisons. The private and third sector will be invited to bid for the construction and operation of these new prisons and places are currently planned to be provided on an uncrowded basis.