Illegal immigration to the United Kingdom

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.[1][2] The methods used to arrive at a figure are also much debated.[3] Problems arise in particular from the very nature of the target population, which is hidden and mostly wants to remain so.[4] The different definitions of 'illegality' adopted in the studies also pose a significant challenge to the comparability of the data. However, despite the methodological difficulties of estimating the number of people living in the UK without authorisation, the residual method has been widely adopted.[5][6][2] This method subtracts the known number of authorised migrants from the total migrant population to arrive at a residual number which represents the de facto number of illegal migrants.[7]

A study carried out by a research team at LSE for the Greater London Authority, published in 2009, estimated the illegal migrant population of the UK by updating the Home Office study.[6] The LSE's study takes into account other factors not included in the previous estimate, namely the continued arrival of asylum seekers, the clearance of the asylum applications backlog, further illegal migrants entering and leaving the country, more migrants overstaying, and the regularisation of EU accession citizens.

The most significant change in this estimate is, however, the inclusion of children born in the UK to illegal immigrants. For the LSE team illegal migrants oscillate between 417,000 and 863,000, including a population of UK-born children ranging between 44,000 and 144,000. 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.[9] A Greater London Authority funded study by researchers at the University of Wolverhampton's Institute for Community Research and Development updated these figures in 2020, and estimated that the figure in April 2017 was between 594,000 and 745,000[5] including between 191,000 and 241,000 children.[5]

  1. ^ Casciani, Dominic (14 June 2006). "An illegal immigration amnesty?". BBC News.
  2. ^ a b Woodbridge, Jo (2005). "Sizing the unauthorised (illegal) migrant population in the United Kingdom in 2001" (PDF). Retrieved 14 March 2022.
  3. ^ "Irregular Migration in the UK: Definitions, Pathways and Scale". The Migration Observatory. University of Oxford. 11 July 2011. Archived from the original on 12 April 2011. Retrieved 22 August 2012.
  4. ^ Sigona, Nando (February 2012). "'I have too much baggage': the impacts of legal status on the social worlds of irregular migrants". Social Anthropology. 20 (1): 50–65. doi:10.1111/j.1469-8676.2011.00191.x.
  5. ^ a b c Jolly, Andrew; Thomas, Sian; Stanyer, James (2020). "London's Children who are not British Citizens: A Profile" (PDF). Greater London Authority. Retrieved 14 March 2020.
  6. ^ a b Gordon, Ian; Scanlon, Kathleen; Travers, Tony; Whitehead, Christine (May 2009). "Economic impact on the London and UK economy" (PDF). GLA Economics. Greater London Authority. Archived from the original (PDF) on 15 September 2015.
  7. ^ Pinkerton, Charles (2004). "Sizing the illegally resident population in the UK" (PDF). ONS. Retrieved 14 March 2020.
  8. ^ "Case Resolution Directorate – Priorities and Exceptional Circumstances" (PDF). UK Visas and Immigration. Home Office. Archived from the original (PDF) on 10 January 2014.
  9. ^ "Undocumented Migrant Children in the UK – COMPAS". Compas. University of Oxford. Archived from the original on 4 March 2016. Retrieved 22 August 2012.