In the case of Lumba v Secretary of State for the Home Department  UKSC 12 the Supreme Court has held that it was unlawful to detain foreign prisoners under a secret policy which was the precise reverse of the publicly declared policy. However, the Court declined to award any more than nominal damages. The Claimants walk away with a total of £1 apiece.
Essentially, the Court holds that because the Claimants would have been detained anyway the unlawfulness is more or less irrelevant and no compensation is due. Remember, this is detention that was against the law, that was not been properly authorised and which was justified by deliberately false reasons by officials in order to conceal the true reasons. To make matters worse it was a deliberate scheme enacted for overtly political purposes, as opposed to mere incompetence.
The Court is silent on the big issues around administrative detention for immigration purposes. Many are concerned that the deprivation of liberty is becoming so commonplace and routine that officials and judges have lost sight of the fact that it represents the ultimate criminal sanction in our society. Plenty of actual criminals who have been convicted do not go to prison, while countless immigrants, who have either not been convicted of an offence or who have served their allotted time in detention, end up serving what would normally be considered a very weighty period of imprisonment reserved for serious offences. See this previous post on the issue by Harriet Grant.
The outcome of Lumba could have been worse. There was a weighty minority judgment to the effect that even detention under a secret policy was not unlawful. It could also have been somewhat better, as there were minority judgments to the effect that nominal compensation was an inadequate remedy.
It might be some consolation to the litigants in Lumba that their own legal costs will no doubt have to be paid by the Home Office, which will amount to quite a tidy sum by now. This is the one fly in the ointment for UKBA, that the judgment permits vindicatory and declaratory legal action to be brought, which could lead to substantial legal costs for the Home Office. However, it seems unlikely that the Legal Service Commission would fund such actions, so the threat is largely illusory.
In criminal law, it is considered better that the guilty walk free than the innocent be convicted. This is the principle behind, for example, the exclusion of coerced evidence: even if the police beat a confession out of a guilty man, that man should be set free, otherwise the police will continue to beat suspects and some innocent men will falsely confess. The same principle should apply in detention cases, otherwise the Home Office will never improve its decision making and processes. Money talks: only the threat of compensation payments would force the Home Office to put its house in order and that opportunity has been lost. A declaration of unlawfulness is like water off the proverbial duck’s back. As a result, it is inevitable that unlawful detention will continue.