Grounds of detention

United Kingdom

Country Report: Grounds of detention Last updated: 10/07/24


Sonia Lenegan

There are no special grounds in legislation for the detention of asylum seekers. They may be detained on the same legal basis as others who are subject to immigration control. There is a power to detain pending examination and a decision as to whether to grant leave to enter or remain; pending a decision as to whether to remove; and pending removal. People who arrive irregularly will often be detained pending initial examination, for example at Manston processing centre for those who arrive via the Channel. The latter two powers are usually used for people who have been unsuccessful in their asylum claim and no longer have permission to be in the UK.

This power may only be exercised if there is a policy reason to detain this person. The Illegal Migration Act 2023 amended the detention powers with effect from 28 September 2023, the main changes are that it is now for the Secretary of State to decide what a reasonable period of detention is for a person and where release is deemed appropriate the person can be detained as long as reasonable necessary while arrangements for release are made.[1] The latter change was made in response to the Secretary of State losing a judicial review challenging delays in arranging asylum accommodation for people in detention.[2]

The five reasons a person can be detained are that:

  • The person is likely to abscond if granted immigration bail;
  • There is currently insufficient reliable information to decide whether to release them (for instance their identity cannot be verified);
  • Removal from the United Kingdom is imminent;
  • The person needs to be detained whilst alternative arrangements are made for their care;
  • Release is not considered conducive to the public good;
  • The application may be decided quickly using the fast track procedures.[3]

Whether a person is likely to abscond is decided on the basis of such factors as whether they have absconded before, whether they have a criminal record, whether they have significant relationships in the UK, whether they have reported regularly to the Home Office if required to do so.

Most asylum seekers are not detained for long periods before their claim is decided, although the introduction of a non-residential short-term holding facility at the former military facility in Manston, Kent, resulted in many people being held for longer than allowed in law. The rapid deterioration in the system is illustrated in the difference between the report of the Prison’s Inspectorate visit in August 2022[4] and the evidence given to a parliamentary committee by the Borders Inspectorate in October 2022.[5]




[1] Illegal Migration Act 2023, s 12, available at:  

[2] Humnyntskyi & Ors, R (On the Application Of) v Secretary of State for the Home Department [2020] EWHC 1912 (Admin), available at:  

[3] Home Office, Detention: General Instructions, September 2023, available at:

[4] HMIP, Report on an unannounced inspection of the short-term holding facilities at Western Jetfoil, Lydd Airport and Manston, April 2022, available at:

[5] Evidence to the Home Affairs Select Committee October 2022, available at:

Table of contents

  • Statistics
  • Overview of the legal framework
  • Overview of the main changes since the previous report update
  • Asylum Procedure
  • Reception Conditions
  • Detention of Asylum Seekers
  • Content of International Protection