The usable operational capacity of the prison estate is 1,700 spaces less than the certified operational capacity. This operating margin reflects the constraints imposed by the need to provide separate accommodation for different groups of prisoners such as gender, age, security category and conviction status, as well as the necessary provision of single cells, accommodation out of use and the geographical distribution of prisons and prisoners.
In April 2004, a database was introduced to assist with the management of the prison population. The more accurate information it provides enabled us to reduce the operating margin in stages from 2,000 to 1,700 places. The reduction added 300 places to the useable operating capacity while still maintaining a sufficient operating margin to manage the prison population safely.
I refer the hon. Member to the reply I gave to the hon. Member for Forest of Dean  about the numbers of prisoners who remain unlawfully at large having absconded from open prisons. In respect of the request for information about court appearances for offences committed by prisoners now recaptured while unlawfully at large, this information is not held centrally by the Prison Service. It would be necessary to interrogate each prisoner’s record and cross check with police and court conviction records which could be done only at disproportionate cost.
All prisoners are categorised objectively according to the likelihood that they will seek to escape and the risk that they would pose should they do so. The likelihood of deportation must be taken into account when considering foreign national prisoner’s allocation to open conditions.