Das, R (on the application of) v Secretary of State for the Home Department & Ors

The immigration-detention policy for a person with serious mental illness requires a purposive and pragmatic, fact-sensitive assessment. A diagnosis alone neither engages nor excludes the policy. The decision-maker must assess the illness's effect on the individual, the effect of detention, and whether the person's actual needs can be satisfactorily managed in the proposed detention setting and period.

The policy does not require illness severe enough for compulsory admission to hospital under the Mental Health Act 1983. If the policy applies, detention requires very exceptional circumstances. Imminent removal, refusal to leave voluntarily, or the mere passage of time will not ordinarily suffice.

Ms Das, an Indian national, sought damages for false imprisonment arising from immigration detention between November 2011 and January 2012. She had received community psychiatric treatment for depression, post-traumatic stress disorder and a learning disability. The Secretary of State did not obtain and consider a psychiatric report known to be available before deciding to detain her.

Sales J in the Administrative Court declared the detention unlawful because the Secretary of State had not made sufficient inquiries to decide whether paragraph 55.10 of the detention policy applied. He nevertheless awarded nominal damages, holding that detention would in substance have been inevitable. Ms Das appealed the interpretation of the policy and the nominal-damages conclusion: [2013] EWHC 682 (Admin).

1. Appeal allowed and matter remitted. The Court held that the judge adopted too high a threshold for a serious mental illness under paragraph 55.10 of the Secretary of State's detention policy. The policy does not confine serious illness to a condition requiring in-patient treatment or compulsory detention under the Mental Health Act 1983.

2. The policy must be construed as a whole, purposively and pragmatically. It is not to be dissected as if it were a statute. Diagnosis is not decisive. The decision-maker must consider the effect of the illness on the particular person, the effect of detention, the available treatment and facilities, and the likely duration of detention. Whether management is satisfactory is fact-sensitive.

3. If the policy applies, there is a high hurdle before detention can be justified by very exceptional circumstances. The relevant balance may include public protection, offending risk, absconding risk and genuinely imminent removal. But liability to removal, refusal to leave voluntarily, proximity of removal, and the simple effluxion of time will not by themselves ordinarily meet that standard.

4. The Secretary of State had to make reasonable inquiries and consider the policy on the available psychiatric material. Although the contemporaneous detention-centre assessments and absence of a Rule 35 report were potentially powerful evidence, the Court could not conclude that Ms Das would and could lawfully have been detained had the policy been correctly applied. She was not an offender, there was no positive evidence that she had breached bail, and the decision-making process had not been explained by witness evidence.

5. The award of nominal damages could therefore not stand. The Administrative Court was to determine whether, on a correct application of the policy, detention would have been lawful and inevitable, and consequently the appropriate damages.

The Court also observed that, whether or not paragraph 55.10 is engaged, a known mental illness requires particular care under the Hardial Singh principles, including consideration of welfare arrangements and monitoring for deterioration.

• Court of Appeal (Civil Division): allowed Ms Das's appeal and remitted the damages issue for further determination.

• Administrative Court: Sales J declared the detention unlawful and a false imprisonment, but awarded nominal damages: [2013] EWHC 682 (Admin).