Table Of Contents
- UK immigration law – who can be detained
- Who can be detained in prison under immigration powers
- Decision to detain excluding where the case is not a criminal casework case
- Who cannot be detained

Immigration detention is a form of administrative detention, which is the process of holding someone temporarily in an immigration removal centre (IRC) or another authorised secure facility while the Home Office considers their immigration position (for example, there may be questions about their visa, asylum claim, right to remain, or whether they have breached immigration rules), removal from the UK, or another immigration matter.
Although there is no rule on how long one should be held in detention, detention must be lawful and reasonable.
You can apply for immigration bail to be released from detention while your immigration case continues or challenge detention if it becomes unlawful.
UK immigration law – who can be detained?
You may be detained under UK immigration law:
• When the Home Office is taking steps to remove you from the UK and detention is considered necessary to help make that removal happen.
• While the Home Office tries to establish who you are or the basis of your immigration claim.
• Where there are reasonable grounds to believe that, if released on immigration bail, you would not follow the conditions imposed on you.
• Where your asylum claim (a request for protection from the UK because you cannot safely return to your own country because you fear persecution or serious harm) has been refused, especially if you do not have a legal right to appeal, or you had a right to appeal, but it has been refused.
• If you have no leave to remain, including if your visa or leave has expired.
• While your immigration case is still waiting for a decision, if there are reasonable grounds to believe that you would not follow the conditions of immigration bail if you were released.
• You are at the UK border, and the Home Office is unsure whether to permit you to enter the UK.
• You are a FNO (Foreign National Offender) person who has just finished a prison sentence. Foreign National Offender is defined as a person who is a non-British citizen who has been convicted of a criminal offence that is serious enough for deportation action. A non-British national may fall within the relevant FNO if they receive a prison sentence of 12 months or more, or a shorter sentence for a serious offence/serious harm. Please note that receiving a caution, fine or community order does not normally put a person into the same FNO category as someone who receives a qualifying prison sentence.
• You are an EEA (European Economic Area) citizen or their family member with an application for EUSS (EU Settlement Scheme) that is yet to be decided, or a pending appeal/ administrative review against refusal of EUSS leave. Where you have an EUSS leave application that is yet to be decided, you will be issued with a CoA (Certificate of Application). A CoA does not itself give you immigration permission to live in or enter the UK; rather, it is evidence that you have made an EUSS application and that can help protect your certain rights, while the EUSS application and any available administrative review or appeal are being decided. Ordinarily, if you have been issued a CoA, you will not be eligible for enforcement action, including detention, until your EUSS application or appeal is finally determined.
• If you are an EEA citizen or their family member who has not applied to the EUSS, applied for it but not had your application validated, or whose EUSS leave has been refused and whose appeal rights exhausted, you may be considered for detention.
Who can be detained in prison under immigration powers?
Prison accommodation is normally used for time-served FNOs who are considered unsuitable for detention in the immigration removal estate.
Several categories in which you may normally remain in, or be transferred to, prison accommodation:
1. National security concerns
For example, specific and verifiable intelligence connecting you with terrorist activities.
2. Serious criminality
This includes certain people convicted of serious Class A drug offences, very serious violent offences involving sentences of 5 years or more, or sexual offences involving a minor.
3. Serious risk of harm to minors
This can include you if you have been identified in custody as presenting a serious risk of harm to children.
4. Certain registered sex offenders
If you are subject to notification requirements on the sex offenders register will usually remain in prison, subject to exceptions.
5. Escape risk
For example, you have escaped from prison, police or immigration custody, or helped someone else escape.
6. Serious disorder or violence in custody
This can include if your involvement in planning or carrying out serious disorder, arson, violence, or serious damage while in custody is found.
Decision to detain excluding where the case is not a criminal casework case
When deciding to detain, the following points must be considered:
• there is a presumption in favour of granting you an immigration bail – This means the starting point is generally to release you on immigration bail rather than detain you. For detention to be justified, there must be strong reasons to believe that you will not comply with the conditions of immigration bail.
• Before authorising detention, the Home Office must consider whether there is a reasonable way of managing your case without detaining you. The purpose is to determine whether detention is actually necessary, rather than using detention when another reasonable option would work.
• The Home Office must look at your specific circumstances. It should not make a detention decision simply because you belong to a particular category of migrants.
• If children are involved, the Home Office must also consider its legal duty to safeguard and promote the welfare of those children.
Who cannot be detained?
There is no statutory (meaning something set out in an Act of Parliament or other legislation) list of people who can never be detained. However, there are important legal limits, policy restrictions (the Home Office has its own detention policies and guidance that caseworkers must follow), and practical prohibitions that mean you can either:
• not be lawfully detained at all, for example, if you are a British Citizen or
• should not normally be detained (except in very exceptional circumstances), such as:
• you are an unaccompanied child or aged under 18. Children are generally not detained for immigration purposes except in very limited circumstances.
• You are an adult who may be “particularly vulnerable to harm in detention” as outlined in the Home Office ‘Adults at Risk (AAR) policy 2016’, such as:
• If you are 70 or over
• You are a pregnant woman (you may be detained in very limited circumstances). Pregnant women are subject to additional restrictions and safeguards.
• You have serious physical disabilities
• You have serious medical conditions and your conditions can only be handled outside of the detention centres. Your physical or mental health can be an important factor when deciding whether your detention is appropriate. Detention may be inappropriate where you cannot be properly managed in detention.
• You have serious mental illness, including if you have PTSD or are a torture survivor
• You are a victim of Trafficking and Modern Slavery
• You are a victim of gender or sex-based violence
• You are transsexual or intersex
• You have been granted bail or have pending appeals
If removal cannot be carried out within a reasonable period, continued detention may become unlawful.
Read Similar Blogs
Can Section 3C Leave Protect Your Immigration Status If Your Visa Expires