The requested information is not available; however, in August 2009 the Control of Immigration Quarterly Statistical publication was expanded to include information on persons entering detention, total number of persons leaving detention and the number of families with children held in detention. This information is available split by age (to separately identify children), and will be published quarterly in the future; however data for earlier years will remain unavailable.
Information on the number of children under the age of 18 entering detention solely under Immigration Act powers in Q1-Q3 2009 by age and country of nationality is available in:
Q1 and Q2 2009
Table 8a and 8b of the Control of Immigration Quarterly Statistical Summary United Kingdom publication
Tables G and H of the supplementary tables
Table 9 of the Control of Immigration Quarterly Statistical Summary United Kingdom publication
Table H of the supplementary tables
Published statistics on immigration and asylum are available from the Library of the House and from the Home Office Research, Development and Statistics Directorate website at: