Written question asked by Viscount Waverley (Crossbench), in the House of Lords. It was answered by Baroness Scotland of Asthal (Labour) on Monday, 18 July 2005.

Economic Migrants

Question: How many illegal short-term economic migrants there have been in the United Kingdom in each of the past five years.

Answer: Information on the number of illegal migrants in the UK, who are either long or short-term economic migrants, in each of the past five years is not available. No government have ever been able to produce an accurate figure for the number of people who are in the country illegally. By its very nature it is impossible to quantify accurately, and that remains the case. Although it is impossible to determine accurately how many people are in the UK illegally, on 30 June 2005 the Home Office published a report which included an estimate of the size of the illegal migrant population in the UK in 2001. It should be noted that the report included an estimate, not an accurate or definitive figure. As mentioned in the report, the only method to estimate the size of the unauthorised migrant population in the UK that currently can sensibly be applied is the residual method. As the method relies on data from the Census of the Population undertaken every 10 years, it is not possible to produce an estimate for a more recent year. A copy of the RDS online report 29/05—Sizing the unauthorised (illegal) migrant population in the United Kingdom in 2001 can be found at www.homeoffice.gov.uk/rds/notes/June—summaries.html.

Secondary information