Individuals awaiting a decision on an immigration claim may be detained under Immigration Powers in prison-like settings. These locations include Short-Term Holding Facilities, Immigration Removal Centres, and prisons themselves.[1]

Where individuals are detained, existing vulnerabilities may be exacerbated. In part, this is due to factors such as poor access to healthcare, insufficient mental health interventions amongst suicidal detainees and patchy legal support within detention settings[2],[3],[4],[5],[6]. The mental and physical health risk factors associated with detention pose significant threats to individuals already made vulnerable by trafficking, and the risk of suicidal ideation and self harm amongst trafficked people within detention is documented[7].

Dr Frank Arnold of Medact explained in an After Exploitation briefing dated 14 February 2020:

“As a doctor I have examined several people who have been trafficked, then arrested and detained for extended periods, and have then very belatedly received reasonable or conclusive grounds decisions by the National Referral Mechanism. Unsurprisingly most displayed strong evidence of traumatisation from the trafficking and persisting exacerbation of PTSD from re-traumatisation.”

To take a trafficked person who is no longer under control of their abusive exploiters and subject them to etention is to substitute one form of powerlessness for another.”

As well as the broader figures on the numbers of victims and potential victims held in detention, it is clear that data on detention and vulnerability more generally would be relevant to the work of modern slavery scholars. However, despite the Home Office confirming to After Exploitation that it holds data on the prevalence of suicide attempts and deaths in detention[9], a subsequent request for concrete figures was rejected on the basis of cost[10].

Data refusals

On nine occasions since the Modern Slavery Act 2015 was introduced, MPs and Lords have been refused data on the detention of modern slavery survivors.

Lord McColl of Dulwich[11], Alex Norris MP[12], Chris Ruane MP[13], David Davis MP[14], Frank Field MP[15], Kate Osamor MP[16], Angela Crawley MP[17] and Louise Haigh MP[18] were refused data on the detention of trafficking victims between 1 June 2015 and 25 September 2020. In four of nine recorded PQ rejections relating to immigration detention and slavery, the Government continued to deny data on the basis that it was not held “centrally” [Appendix: PQ table].  We are concerned that this data was refused, given the significant emotional and practical impact detention has on survivors.

After Exploitation’s research reveals that between 2017 and 2019, whilst Parliamentarians were being denied this exact data, the detention of potential victims was rising by 206%[19]

Home Office statistics on the immigration
detention of individuals with NRM decisions
YEAR OF DETENTIONPOTENTIAL (positive Reasonable Grounds)CONFIRMED* (positive Conclusive Grounds)
* Some potential victims will still be awaiting a final decision on their trafficking claim, as the mean waiting time for a conclusive grounds decision is 14 months

Home Office guidance emphasises that vulnerable adults should only be detained “where immigration consideration outweighs any risk identified” such as cases where individuals may hold ‘foreign national offender’ status[20]. However, a subsequent FOI request by After Exploitation found that only 11% (n=54) of potential trafficking victims detained (n=507) and 21% (n=5259) of the total detention population in 2018 (n=24,773) held FNO status[21]. This preliminary data raises serious questions around the ‘immigration considerations’ being used to detain people, as so few are recognised offenders. Even in cases were trafficking victims do hold FNO status, this does not necessarily reflect diminished vulnerability. For example, data on FNO status may reflect crime committed as a result of exploitation, such as forced theft or drug cultivation.

In the absence of official data on the detention of potential and recognised victims, the practice of detaining survivors has grown exponentially each year.


The Government must improve data reporting on vulnerability and risks in detention amongst the general detainee population. Recorded risk outcomes, such as cases of suicide, suicide attempts, deaths in detention and self harm, should be released publicly.  On modern slavery, the Government should report the detention of victims and potential victims as part of the Secretary of State’s Annual Modern Slavery Report, or in a quarterly format similar to the Home Office’s existing detention statistics.

[1] Right to Remain (2020). Toolkit, accessible:


[3] Lousley, G., et al (2017). We are still here. Women for Refugee Women

[4] McGinley, A., Trude, A., (2012). Positive duty of care? The mental health crisis in immigration detention, AVID and BID

[5] Helen Bamber Foundation (2017). Submission to the 2017 stephen shaw review of welfare in Detention of vulnerable persons, Helen Bamber Foundation. Last accessed 12 June 2019:

[6] Sceats, S., (2015). Freedom From Torture submission to the Shaw Review, Freedom From Torture. Last accessed 21 June 2020:

[7] Katona, C., Robjant, K., Shapcott, R., Witkin, R., (2015). Addressing the mental health needs in survivors of modern slavery, Freedom Fund & Helen Bamber Foundation. Accessible:


[9] Accessible:

[10] Accessible:









[19] Accessible:

[20] Home Office (2019), Adults at Risk in Immigration Detention, Version 5.0. Pg 4, Last accessed 15 September 2020: