Immigration detention in the UK

The Heathrow immigration detention complex including Harmondsworth and Colnbrook detention centres is the centrepiece of the UK detention regime, one of the largest and most repressive immigration detention systems in Europe.

People in detention

Around 2000 people at any time are detained in the UK under Immigration Act powers. In 2018 24,748 people were sent into detention.

Around 90% of detained people are men, or are classified as male by the Home Office. In 2018 63 children, including 16 aged under five years, entered detention.

People are imprisoned in the immigration detention system to facilitate enforcement of immigration rules, not because they have been convicted of any crime. The Home Office’s enforcement instructions and guidance set out five grounds under which a person may be detained; many of these are quite broad and in practice many people are held when there is no reason to believe they would pose a threat if not detained. A minority of detainees (about a quarter of those entering detention in the first quarter of 2019) are ‘foreign national offenders’, people who are detained indefinitely after completing a prison sentence. Like other detainees these people are held because of their immigration status not because of their convictions: they are imprisoned while a British national with the same conviction and prison sentence would be free.

Between 2000 and 2015 asylum seekers could be detained while their cases were assessed under the ‘detained fast track’ policy, purely for administrative convenience and largely on the basis of their country of origin. In 2015 this policy was found unlawful and suspended; asylum seekers may still be detained but only when there are other grounds for detention.

Indefinite detention

The vast majority of immigration detainees in the UK are held indefinitely with no limit on the length of their imprisonment (families with children and pregnant detainees are usually limited to 72 hours of detention, although this may be extended in some circumstances with ministerial approval). The UK is the only EU member state to detain people indefinitely for immigration purposes.

In practice people are often detained for long periods: of those leaving detention in 2018, while about 30% were detained for three days or less, about the same number were held for more than 28 days and about 4% (over 1000 people) were in detention for more than six months. Some people are detained for much longer, occasionally as long as six years.

Places of detention

Immigration detainees are held across the UK: in May 2019 at seven dedicated detention centres (including Harmondsworth and Colnbrook), three short-term holding facilities (including one at Heathrow), a ‘pre-departure accommodation’ facility near Gatwick airport for families with children, and in ordinary prisons (in 2018 around 3000 people were held in prisons under Immigration Act powers). Most detention centres are run for profit by private contractors; the exception is Morton Hall in Lincolnshire, operated by HM Prison Service.

The financial cost of detention

The total cost of the immigration detention system in the year up to March 2018 was £108 million according to Home Office figures. The average cost of detaining one person for one day was £88.68 in the first quarter of 2019. These figures do not include legal and administrative costs or compensation paid to wrongly detained people, so the true cost of detention is higher even when measured in purely financial terms, leaving aside the immeasurable human and social costs.

Criticism and the future of detention

The UK immigration detention system has been repeatedly criticised over the years by campaigners, politicians, academics and organisations supporting migrants. Successive governments have resisted calls for detention to be abolished and until recently have been expanding the detention regime, particularly between 1993 and 2015 when total detention capacity rose from around 250 people to over 3500. Since then criticism from a range of sources has prompted changes in policy and the number of people detaineed has been falling since 2015.

In 2014–2015 two All-Party Parliamentary Groups, on refugees and migration, carried out an inquiry into the use of immigration detention in the UK. The report recommended a time limit of 28 days and found that the decision to detain was made too frequently, recommending community-based alternatives to detention wherever possible.

In 2015 the then Home Secretary, Theresa May, commissioned an independent report by Steven Shaw, former Prisons and Probation Ombudsman for England and Wales, into the impact of Home Office policies and procedures on the welfare of immigration detainees. The first report was published in 2016 and in a follow-up report in 2018 Shaw assessed the government’s progress in implementing the first report’s recommendations. Both reports recommended changes that would have the effect of reducing the number of people detained, including expanding the categories of vulnerable people who should only be detained in exceptional circumstances and exploring community-based alternatives to detention.

The call for a 28-day limit on detention, recommended in 2015 by the All-Party Parliamentary Groups on refugees and migration, is now endorsed by a growing chorus of campaigners, experts and politicians. It has been included in several political parties’ manifestos and a bill currently before parliament would amend the 1971 Immigration Act to introduce a 28-day limit.

As a result of all these developments the number of people detained in the UK has been falling, from a peak of 32,447 people detained in 2015 to 24,768 in 2018. Since 2015 four dedicated detention centres have been closed without replacement; the only new detention facilities to open in this period have been replacements for closed short-term facilities at Manchester and Gatwick airports. If the government continues to implement the recommendations of the Shaw reviews, or if a 28-day limit is introduced, the demand for detention places will fall further, calling into question the need for a new detention centre at Heathrow if Harmondsworth and Colnbrook detention centres are demolished to make way for the airport’s expansion.