Woodbridge

Does not include in his definition those who have a legal right to remain but have breached the condition (e.g. By working) unless their right to remain has been revoked.1
points to adaptation made to the North American residual method to apply to the UK.2 claims that emigration is more common in the first two years of arrival in the UK.3
“The unauthorised resident population in the UK in April 2001 has a central estimate of 430,000, and a
range (based on taking all the most extreme assumptions discussed in Annex 3) of 310,000 to
570,000. These 430,000 unauthorised immigrants living in the UK in 2001 constituted 0.7 per cent of
the total UK population of 59 million. This compares to seven million unauthorised migrants in January
2000 in the US,9 2.5 per cent of the total US population of just over 281 million, using the same
method. The comparison is especially positive for the UK when one considers that the US
unauthorised population has been reduced by amnesties.”4
1J Woodbridge, Sizing the Unauthorised (Illegal) Migrant Population in the United Kingdom in 2001, Home Office Online Report 29/05 available online at http://www.homeoffice.gov.uk/rds/pdfs05/rdsolr2905.pdf [Accessed October 15 2008] 1.
2J Woodbridge, Sizing the Unauthorised (Illegal) Migrant Population in the United Kingdom in 2001, Home Office Online Report 29/05 available online at http://www.homeoffice.gov.uk/rds/pdfs05/rdsolr2905.pdf [Accessed October 15 2008] 2–4.
3J Woodbridge, Sizing the Unauthorised (Illegal) Migrant Population in the United Kingdom in 2001, Home Office Online Report 29/05 available online at http://www.homeoffice.gov.uk/rds/pdfs05/rdsolr2905.pdf [Accessed October 15 2008] 4.
4J Woodbridge, Sizing the Unauthorised (Illegal) Migrant Population in the United Kingdom in 2001, Home Office Online Report 29/05 available online at http://www.homeoffice.gov.uk/rds/pdfs05/rdsolr2905.pdf [Accessed October 15 2008] 5.