Colnbrook Immigration Removal Centre is located in Harmondsworth, London Borough of Hillingdon.
Colnbrook, adjacent to Harmondsworth Immigration Removal Centre and London Heathrow Airport, houses only males.
Colnbrook, which opened in August 2004, is built to Class B prison standards, making it one of the highest security immigration removal centres in the United Kingdom alongside Brook House.
The design of the centre is modelled on a high security, Category B criminal prison with wings running into a central area.
Colnbrook detains people who are due for removal from the UK due to inadequate right to enter or to remain in the United Kingdom and this may include foreign-national prisoners who have completed their sentences in UK prisons and who are detained pending removal from the country.