The Home Office is responsible for ordering detention of asylum seekers. There is no maximum period set in law, with the exception of detention of pregnant women and children which cannot exceed 72 hours, or 7 days with Ministerial approval.
While data on length of immigration detention is now available for the last six years, the figures do not distinguish between asylum seekers and other immigration detainees. Periods of immigration detention including asylum seekers and other foreign nationals vary enormously from a few days to several years. During 2023, 15,354 left immigration detention.[1] Of these:
| Duration of stay in detention 2018 – 2023 | ||||||
| 2018 | 2019 | 2020 | 2021 | 2022 | 2023 | |
| Less than 29 days | 17,655 | 18,076 | 11,968 | 21,074 | 14,150 | 9,346 |
| From 29 days to 2 months | 3,489 | 3,622 | 1,770 | 1,428 | 2,862 | 3,007 |
| From 2 to 4 months | 2,401 | 1,869 | 1,023 | 1,061 | 1,610 | 1,910 |
| From 4 months to 12 months | 1,752 | 849 | 641 | 710 | 735 | 942 |
| From 1 to 2 years | 188 | 122 | 100 | 79 | 72 | 110 |
| At least 2 years | 14 | 6 | 8 | 10 | 18 | 39 |
Source: Home Office, Immigration Statistics, Detention.
The longest periods of detention are usually of people awaiting deportation after having served a criminal sentence.
[1] Home Office, Immigration system statistics data tables, Immigration detention detailed datasets, year ending December 2023, table Det_03, available at: https://tinyurl.com/bdhnwfkr.