The longest time a person has been detained in the immigration estate - a foreign criminal who who left detention and was returned to Algeria in Q1 2012 - was 2,319 days.
The individual in this case had accumulated 14 convictions from 32 offences committed between 1998 and 2004, including - but not limited to - convictions for firearms/ shotguns/offensive weapons, drug offences, offences relating to police/courts/prisons and theft. He was continuously non-compliant with the Home Office and Algerian authorities, using a false identity and nationality, which frustrated attempts to obtain travel documentation to facilitate his deportation. His continued non-compliance, deception and a history of absconding led to detention being prolonged.
This information does not include those held in prisons solely under Immigration Act powers.
The Home Office publishes quarterly and annual statistics on the number of people detained in the United Kingdom for immigration purposes, within the Immigration Statistics release on the GOV.UK website: https://www.gov.uk/government/organisations/home-office/series/immigration-statistics-quarterly-release