It is difficult to measure how many people reside in the UK without authorisation, although a Home Office study based on Census 2001 data released in March 2005 estimated a population of between 310,000 and 570,000.
Drawing on this and taking stock of the outcome of the recent Case Resolution Programme,[8] a University of Oxford study by Nando Sigona and Vanessa Hughes estimated at the end of 2011 a population of illegal migrant children of 120,000, with over half born in the UK to parents residing without legal immigration status.
[15] Migration Watch UK has criticised the Home Office figures for not including the UK-born dependent children of illegal migrants.
[19] Analysis by the Institute for Public Policy Research suggested that an amnesty would net the government up to £1.038 billion per year in fiscal revenue.
[20] However, analysis by MigrationWatch UK suggests that if the migrants granted amnesty were given access to healthcare and other benefits, the net cost to the exchequer would be £5.530 billion annually.
[25] Nigel Farage of the UK Independence Party criticised the campaign as "nasty" and suggested that its real message was "Please don't vote UKIP, we're doing something".
[citation needed] In January 2025, the UK implemented a pioneering sanctions regime targeting people smugglers by cutting off the illicit financial support that sustains their activities.
The initiative, announced by David Lammy, includes measures such as asset freezes and travel bans, alongside a £150 million-funded Border Security Command to boost surveillance and intelligence efforts.
Priti Patel condemned the government's decision to abandon the Rwanda deportation scheme, raising doubts about the overall impact on curbing illegal migration.
[31] Simon Murray, the undersecretary of state for the Home Office, defended the bill, saying the nation's asylum system and budget were overwhelmed and that removing the possibility of staying in the UK is the only way to prevent smugglers from exploiting would-be migrants.