Question to the Home Office:

To ask the Secretary of State for the Home Department, how many illegal immigrants are estimated to currently reside in the UK.

In June 2019, the Office for National Statistics (ONS) published a note on ‘measuring illegal migration’.

By its very nature, it is not possible to know the exact size of the illegal population and so we do not seek to make any official estimates of the illegal population. The Government is focused on making it harder for people to enter and live in the UK illegally whilst ensuring those who have the right to reside in the UK can do so. Exit checks introduced in April 2015 will, over time provide more detailed insights into the behaviour of migrants and how they comply with the restrictions placed upon their length of stay in the UK, but the data obtained does not provide the total number of illegal migrants currently in the UK.