[holding answer 28 February 2007]: The requested information is not available.
However, the labour force survey has been used to estimate take-up rates of British citizenship and these entail some estimates of the number of non-British citizens in the UK; these are published in the Home Office Statistical Bulletin “Persons Granted British Citizenship United Kingdom, 2005”, which may be obtained from the Library of the House and from the Home Office website at:
http://www.homeoffice.gov.uk/rds/immigration1.html