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Immigration Detention in the UK

16 Sep 2021

This briefing provides an overview of immigration detention in the UK. It discusses the capacity of the UK’s detention system, the number of people detained, their characteristics, and lengths of detention. It also examines the detention of children and the financial costs of operating the system.

  1. Key Points
    • COVID-19 substantially reduced the use of immigration detention in the UK.
    • In 2020, around 15,000 people entered immigration detention in the UK, down from 24,000 in 2019.
    • From 2009 to 2019, the daily population of immigration detainees ranged from around 1,600 to 3,500, before falling to a record low in 2020 due to COVID-19.
    • In 2020, the Home Office detained 23 children for immigration-related purposes, down from 98 in 2019 and around 1,100 in 2009.
    • From 2010 to 2020, citizens of ten countries constituted over 60% of all people entering immigration detention.
    • In 2020, around three quarters of immigration detainees were held for less than 29 days.
    • In 2020, around a quarter of people leaving detention were immediately removed from the UK, down from 64% in 2010; most of the rest were released on bail.
    • Around half of those entering immigration detention have previously claimed asylum in the UK.
    • The Home Office estimates that at least 112 members of the Windrush generation may have been unlawfully detained.
    • In Q2 2021, the average cost to hold one person in immigration detention was around £99 per day.
  1. Understanding the Policy

    Immigration detention refers to the Home Office practice of detaining foreign citizens for the purposes of immigration control. Policy reasons for detaining typically include one or more of the following: to remove the person from the UK; to establish their identity or the basis of their immigration or asylum claim; where there is reason to believe they will abscond if released on bail; or when release is not considered to be ‘conducive to the public good’. In some instances, the reasons for a person’s detention change while they are being held. Detention typically ends in either removal from the UK, or release, usually on immigration bail. ... Click to read more.

    The Home Office has the administrative power to detain a person at any point in their immigration process. This includes: upon arrival in the UK; upon presentation to an immigration office within the country; during a check-in with immigration officials; once a decision to remove has been issued; following arrest by a police officer; or after the conclusion of a prison sentence.

    The Home Office detains people in Immigration Removal Centres (IRCs), prisons, Short-Term Holding Facilities (STHFs), pre-departure accommodation facilities (PDAs) and short-term holding rooms based at ports of entry. Immigration detention is an administrative process, rather than a criminal justice procedure, meaning that the decision to detain a person is typically made by Home Office civil servants rather than courts, although it can result from a court decision regarding deportation.

    On 30 June 2021, 64% (985) of those in immigration detention were held in IRCs, 0.5% (7) in STHFs, and nobody was held in pre-departure accommodation (short-term holding rooms are not included in these counts). It is notable that 36% (558) were held in prisons under immigration powers, up from 10% (330 out of 3,455) in the third quarter of 2017, when statistics on the number of people detained in prisons first began to be officially published.

    Detention is meant to be used as a last resort. According to Home Office policy and international law, “Detention must be used sparingly, and for the shortest period necessary” (UK Visas and Immigration, 2016, para. 55.1.3). As of 15 January 2018, Schedule 10 to the Immigration Act 2016, on Immigration Bail, introduced automatic bail hearings for detainees. Detention beyond this period must be authorised by senior officials within the Home Office. Unlike other European countries, in the UK there is no upper time limit on how long a person can be detained (see below).

    The UK’s detention system

    As of 30 June 2021, the UK’s detention system comprised:

    • six IRCs: Brook House, Colnbrook, Dungavel, Harmondsworth, Morton Hall, and Tinsley House;
    • Yarl’s Wood, previously an IRC but repurposed in August 2020 as a short-term holding facility for men (though it continues to operate as an IRC for some women);
    • two residential short-term holding facilities to hold people for up to a week: Manchester STHF (formerly Pennine House), and Larne House STHF;
    • one pre-departure accommodation facility at Gatwick Airport within Tinsley House, which was closed due to the pandemic from 27th March 2020 for the rest of the year;
    • short-term detention units for up to one week located within some IRCs, including the Sahara Unit for women within Colnbrook IRC;
    • several holding rooms run by Border Force in ports, airports, and at reporting centres across the country; and
    • prisons, in which the UK also detains people for immigration-related reasons (Home Office, 2021b).

    All the above facilities are in England, except for Dungavel IRC in Scotland, and Larne House STHF in Northern Ireland.

    As part of the juxtaposed controls system established by the Sangatte and Touquet treaties, the UK Border Force subcontracts operational responsibility for four STHFs in Northern France. Two STHFs are in Coquelles: one inside the Eurotunnel site, and one at the port of Calais. The private contractor Mitie Care and Custody holds the contract to manage these three STHFs. Eamus Cork Solutions manages the fourth STHF, which is located in Dunkerque (Dunkirk).

    There are 14 reporting centres in the UK, where some detainees are first detained and where many must subsequently report routinely as a condition of their release. In March 2020, the Home Office announced the temporary suspension of reporting as a condition of immigration bail due to the COVID-19 pandemic.

    The Home Office has outsourced the management of the IRCs to private, for-profit prison firms. Until recently this included the GEO Group, which managed Dungavel, and G4S, which managed Brook House and Tinsley House. From late September 2021, Mitie and Serco have been managing all the IRCs. Mitie runs the Heathrow IRCs (Colnbrook and Harmondsworth), it took over Dungavel from GEO in 2021, and has the contract for a new IRC, Derwentside. Serco manages Yarl’s Wood as well as Brook House and Tinsley House at Gatwick Airport. In 2011, the contract for managing the holding rooms, and two of the three STHFs, passed to Reliance (now Tascor).

    The Home Office has closed several IRCs in recent years as part of a planned reduction of the UK’s detention system. IRCs Dover and Haslar closed in 2015. The Verne closed in December 2017 and returned to its previous purpose as a men’s prison. Campsfield House closed in December 2018. Morton Hall has returned to prison use, though with a residential STHF on site for men and women.

    Between 2011 and 2016, the Cedars Pre-Departure Accommodation operated in West Sussex, where the charity Barnardo’s oversaw welfare services delivered to families detained for short periods before removal. A “discrete self-contained unit” at Tinsley House IRC opened to accommodate families in May 2017. Families can be held for up to 72 hours, with a ministerial declaration for “exceptional” cases extending a family’s stay to no more than seven days.

    Women in immigration detention

    The detention of women, and especially pregnant women, has attracted particular criticism. Most notably, Yarl’s Wood, which until August 2020 was the main IRC for women, was described in a 2015 report by Her Majesty’s Inspector of Prisons as a “place of national concern”, though a 2017 inspection reported “significant improvements”.

    Home Office policy states that pregnant women may be detained only if removal is imminent or there are exceptional circumstances to justify detention. In 2016, a 72-hour time limit on the detention of pregnant women was enacted, although a government minister can extend this to a maximum of seven days.

    A new IRC called Derwentside is due to open in County Durham in October 2021. Previously known as Medomsley or the Hassockfield Secure Training Centre for young offenders, Derwentside will become the only IRC solely for women, with a capacity of 84 beds (Legal Aid Agency, 2021, p. 8). Small numbers of women can also be detained at Colnbrook (called Colnbrook STHF in Home Office statistics) and Dungavel, in residential STHFs like Manchester and Larne House, and in the Kent Intake Unit at Dover.

    Housing asylum seekers in Penally Camp and Napier Barracks

    During the COVID-19 pandemic, the Home Office has been holding asylum seekers have been held in “contingency” accommodation, in response to an increase in migrants arriving from France in small boats (see our Q&A: Migrants crossing the English Channel in small boats). From 21 September 2020, this included two military sites: Penally Training Camp in Wales (which held around 200 people at its peak (Neal, 2021, p. 33); and Napier Barracks in Folkestone (which housed around 400 asylum seekers at its peak in January 2021 (Neal, 2021, p. 12)). Penally Camp was closed on 21 March 2021. On 3 June 2021, the High Court ruled that accommodating asylum seekers at Napier Barracks was unlawful: conditions did not meet minimum legal standards for asylum accommodation; and detaining people during a COVID-19 outbreak violated the European Convention on Human Rights. The judge described the conditions as “detention-like” (p. 39). The Guardian reported that as at 22 June, around 230 asylum seekers continued to be housed in Napier, though the Home Office had suspended transfers there.

  1. Understanding the Evidence

    The publicly available data on immigration detention are found primarily in publications of the Home Office and Her Majesty’s Inspectorate of Prisons (HMIP). The detention statistics record people detained under Immigration Act powers, and not foreign nationals serving criminal sentences. The statistics exclude people detained for less than 24 hours in short-term holding rooms at seaports, airports and police cells. ... Click to read more.

    Data on those entering detention are counts of the number of occurrences of people entering detention rather than the number of unique individuals. Thus, an individual who enters detention, say, twice in a given period, would be counted twice in the data. Nevertheless, in this briefing we use the term “people entering detention” for ease of expression.

    Data on those detained in prison are included from Q3 2017 onwards, but do not include people detained in police cells and short-term holding rooms at ports and airports (for less than 24 hours), and those detained under both criminal and immigration powers and their dependants. As such, counts from Q3 2017 onwards are not comparable with those for earlier periods.

    Data on those in detention relate to those in detention on the last day of the quarter.

COVID-19 substantially reduced the use of immigration detention in the UK

COVID-19 significantly reduced immigration detention in the UK (Figure 1). During 2020, both the number of people entering detention and the detainee population fell substantially, especially during Q2 2020, though numbers returned to pre-pandemic levels in Q2 2021. There was also a decline in the number of people removed from the UK from detention, though this has not returned to pre-pandemic levels.

In March 2020, the charity Detention Action took legal action against the government, challenging the lawfulness and safety of continued immigration detention during the Covid-19 pandemic and calling for release of all immigration detainees. The High Court dismissed the case, but the Home Office nonetheless stated that they would review the cases of all people detained. Many people were released on immigration bail (especially in the third and fourth quarters of 2020), and removals from the country were significantly reduced, with removals to some countries suspended entirely.

Figure 1

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In 2020, around 15,000 people entered immigration detention in the UK, down from 24,000 in 2019

From 2009 to 2020, the number of people entering detention each year has ranged from around 15,000 to 32,000 (Figure 2). The number increased each year from 2010, reaching a peak of 32,447 people entering detention in 2015. Thereafter, the number of people entering detention has reduced each year.

In 2020, around 15,000 people entered detention, down 40% on 2019 and around 55% lower than its peak in 2015. This number was by far the lowest since 2009 when the current official data series begins.

In any given year, a large majority of those entering detention are men – between 81% and 94% – with 2020 recording the smallest share of women entering detention: 7%.

Figure 2

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From 2009 to 2019, the daily population of immigration detainees ranged from around 1,600 to 3,500, before falling to a record low in 2020 due to COVID-19

On 31 October 2018, the combined capacity of the UK’s seven IRCs, two STHFs, and pre-departure accommodation at Gatwick Airport was around 2,800 (Bolt, 2020, p. 19). Capacity will change with the opening of Derwentside in October 2021 (+84 beds), the closure of Morton Hall IRC (-400 beds), and the opening of Morton Hall STHF (+35 beds).

From 2009 to 2020, the Home Office detained between around 700 to 3,500 people at any given time (Figure 3).

At the end of June 2021, there were 1,550 people detained under Immigration Act powers, including 558 people detained in prisons, the second highest number detained in prisons since official records began in 2017 (at the end of March 2021, there were 577 people detained in prisons). The fall in numbers after 2015 likely resulted from a 2016 legal challenge to charter flights, and the end of the Detained Fast Track policy, which ran from 2000 until July 2015 and enabled the detention of asylum seekers if a quick decision on their case was likely. The Home Office also closed the following IRCs: Dover and Haslar in 2015, which provided a combined total of approximately 600 places, The Verne in 2017 (600 places); and Morton Hall in 2021 (400 places).

Home Office analysis has suggested that falls in the detained population in 2018 might have resulted from (1) the commencement on 15 January 2018 of Schedule 10 to the Immigration Act 2016, on Immigration Bail, which introduced automatic bail hearings for detainees four months after entering detention; and (2) changes to the immigration system following the Windrush situation (Home Office, 2019a). Post-Windrush changes included colleagues checking caseworker decisions, and increasing face-to-face contact time between caseworkers and detainees (Joint Select Committee on Human Rights, 2019). The COVID-19 pandemic also contributed to the decline in the detained population, as explained above.

Figure 3

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In 2020, the Home Office detained 23 children for immigration-related purposes, down from 98 in 2019 and around 1,100 in 2009

In recent years, few under-18s or people who are 50 or older have entered detention. In 2020, 96% of people entering immigration detention were between 18 and 49 years old (Figure 4).

In the 1990s, the Home Office rarely detained families with children. By contrast, between 2005 and 2009, non-governmental organisations and other groups estimated that the number of children detained with their families was up to 2,000 per year (Crawley and Lester, 2005; Sankey et al., 2010).

Home Office statistics record that in 2009, 1,119 children entered detention. After a policy change under the Conservative and Liberal Democrat coalition government, and the opening of Cedars pre-departure accommodation, the number of detained children fell substantially, and stood at an all-time low of 23 in 2020 (Figure 4).

Figure 4

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From 2010 to 2020, citizens of ten countries constituted over 60% of all people entering immigration detention

Of the roughly 15,000 people who entered immigration detention in 2020, 62% were citizens of ten countries (Table 1). In part, these patterns reflect the total number of people of each nationality in the UK.

The number of EU citizens entering immigration detention has increased significantly over the past decade, from 768 in 2009, to a peak of 5,319 in 2017. The numbers fell in subsequent years, and in 2020 EU citizens made up 17% of all those entering detention (Figure 5). The majority of EU citizens detained in the UK are from Eastern Europe, including Romania and Poland.

Table 1

Figure 5

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In 2020, around three quarters of immigration detainees were held for less than 29 days

Unlike most European countries, the UK has not legislated a statutory upper time limit on the period that an individual can be held in immigration detention. Of all people leaving detention in 2020, 77% had been detained for less than 29 days, 11% for 29 days to under 2 months, 9% for 2 months to under 6 months, 2% for 6 months to under 1 year, and 0.7% had been detained for 1 year or longer (Figure 6).

Female detainees are on average held for shorter periods than male detainees (Figure 6).

At the end of March 2021, the person who had been in immigration detention for the longest had been detained for over three years (Home Office, 2021a, Det_03d)

Campaign groups and health professionals have argued that the uncertainty surrounding a person’s length of detention is harmful to detainees and their family and friends. A range of stakeholders have argued for legislating a maximum limit on individual periods of detention, including: HM Chief Inspector of Prisons (2017); the All Party Parliamentary Group on Refugees and the All Party Parliamentary Group on Migration (2015); and the House of Commons Home Affairs Committee (2019).

Figure 6

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In 2020, around a quarter of people leaving detention were immediately removed from the UK, down from 64% in 2010; most of the rest were released on bail

Over the last decade, there has been a long-term fall in the share of people leaving immigration detention to be returned to their country of nationality or habitual residence. In 2010, 64% of people leaving detention directly left the UK – either voluntarily or under Home Office enforcement. In 2020, this had fallen to a record low of 26% (Figure 7).

A Home Office report, Issues raised by people facing return in immigration detention, points to an increase in detainees raising “issues”, such as asylum claims or legal challenges, to prevent their return. The Home Office has credited the COVID-19 pandemic-related travel restrictions as making it more difficult to secure removals and, hence, a cause of the decline (Home Office, 2021c).

Figure 7

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Around half of those entering immigration detention have previously claimed asylum in the UK

There are several categories of people who are detained under Immigration Act powers. Some individuals fall into more than one category. These categories include: new arrivals awaiting examination by an immigration officer to determine their right to enter the UK; new arrivals who have been refused permission to enter the UK and are awaiting removal; those who have either failed to leave the UK on expiry of their visas (visa overstayers), or who have not complied with the terms of their visas, or have attained their visas by deception; and people in the UK who are awaiting a decision on whether they are to be removed, or who are awaiting their removal, such as refused asylum seekers.

The largest category of immigration detainees comprises people who have sought asylum at some stage during their immigration process, including while in detention. In 2020, detainees who had sought asylum accounted for 65% (9,620) of people entering detention (Home Office, 2021a, Det_01).

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The Home Office estimates that at least 112 members of the Windrush generation may have been unlawfully detained

In some cases, long-term legal residents or even British citizens who are unable to prove their status have been detained, as illustrated by the 2018 Windrush situation (see Williams, 2020). The Home Office Windrush Historical Cases Review examined the immigration records of 11,800 British residents of Caribbean Commonwealth nationality who were born before 1973 and who had been held in immigration detention or removed from the UK since 2002. The review found that 112 such members of the Windrush generation had been detained, of whom 31 were removed (Home Office, 2019b; see also Williams, 2020). The government has not been able to confirm whether all of these individuals were in fact unlawfully detained, because it has not been able to trace nine of them.

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In Q2 2021, the average cost to hold one person in immigration detention was around £99 per day

The annual financial cost of the UK’s detention system for the year ending March 2021 was around £95 million, down from around £144 million in the year ending March 2014 (Figure 8, left chart). The lower costs are in large part due to reductions in the size of the detention system, and fewer people being held in immigration detention.

The average daily cost of keeping an individual in immigration detention has remained fairly constant over the last eight years, ranging from a low of £85 to a high of £102. In Q2 2021, the estimated average cost of holding someone in immigration detention was £98.78 per day (Figure 8, right chart).

Figure 8

Courts may order the Home Office to compensate people who have been unlawfully detained. In recent years, the Home Office has issued an increasing number of compensation payments for wrongful detention. In the year ending March 2021, there were 330 proven cases of wrongful detention, for which a total of £9.3m was paid in compensation – up from £0.8 million for 38 cases in 2014-15 (Figure 9).

Figure 9

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Evidence Gaps and Limitations

There are two notable deficiencies in the available data on immigration detention in the UK. First, as mentioned, it is not possible to track individual trajectories of detention, release, and re-detention through the statistics, because the Home Office presents separate numbers of occurrences. Second, the Home Office does not provide information in the public statistics about how many people are being held on which policy ground for detention, and whether they have been released from detention or removed from the UK.


With thanks to Mary Bosworth, Ali McGinley, Gemma Lousley at Women for Refugee Women, and officials at the Home Office for extremely helpful comments on drafts of this briefing. We are also grateful to CJ McKinney of, and Bella Sankey of Detention Action, for thorough and detailed comments on the 2020 update of this briefing. Final thanks go to Frances Timberlake of Refugee Rights Europe, for information on short-term holding facilities in Northern France.


Related Material

  1. Media Coverage
    • Independent (26 Oct 2016)

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