The Home Office is responsible for ordering detention of asylum applicants. 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. The Illegal Migration Act 2023 contains powers to detain children without a time limit, however these were never commenced and the Border Security, Asylum and Security Bill will repeal these provisions.
During 2024, 7,631 asylum applicants and 12,791 non-asylum applicants left immigration detention.[1] While data on length of immigration detention is available, the figures do not distinguish between asylum applicants and other immigration detainees. Periods of immigration detention including asylum applicants and other foreign nationals vary enormously from a few days to several years.
| Duration of stay in detention 2019 – 2024 | ||||||
| 2019 | 2020 | 2021 | 2022 | 2023 | 2024 | |
| Less than 29 days | 18,076 | 11,968 | 21,074 | 14,150 | 11,539 | 13,437 |
| From 29 days to 2 months | 3,622 | 1,770 | 1,428 | 2,862 | 3,151 | 3,681 |
| From 2 to 4 months | 1,869 | 1,023 | 1,061 | 1,610 | 1,980 | 2,142 |
| From 4 months to 12 months | 849 | 641 | 710 | 735 | 1,004 | 1,065 |
| From 1 to 2 years | 122 | 100 | 79 | 72 | 118 | 85 |
| At least 2 years | 6 | 8 | 10 | 18 | 46 | 12 |
Source: Home Office, Immigration Statistics, Detention, table Det_D03.
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 2024, table Det_01, available here.