Currently we do not publish data relating to the number and locations of individuals held in prison solely for immigration purposes. However, the quarterly immigration statistics are kept under review, taking into account the needs of users and burdens on suppliers and producers in line with the Code of Practice for Official Statistics.
The Home Office publishes quarterly and annual statistics on the number of people detained in the United Kingdom for immigration purposes, within Immigration Statistics. The data on people in detention are readily available in the latest release, “Immigration Statistics: April to June 2013”, from the gov.uk website:
Published figures on people detained in the United Kingdom solely under Immigration Act powers include those held in short term holding facilities, pre departure accommodation and immigration removal centres. Figures exclude those held in police cells, Prison Service establishments, short term holding rooms at ports and airports (for less than 24 hours) and those recorded as detained under both criminal and immigration powers and their dependants.