http://www.migrationwatchuk.org/frameset.asp?menu=news&page=newsdesk.asp
"The recent Home Office estimate of unauthorised (illegal) migrants was four years out of date. It estimated the number to be between 310,000 and 570,000 with a central estimate of 430,000.
2. This estimate should be adjusted to include failed asylum seekers in subsequent years and the UK born children of illegal immigrants.
3. Taking these two factors into account Migration Watch estimates that the current population of unauthorised migrants is in the range 515,000 to 870,000 with a central estimate of 670,000. However, other factors point towards the upper end of this range. "
