In R (DN – Rwanda) v Secretary of State for the Home Department  UKSC 7, the Supreme Court held that the Claimant was entitled to purse a claim for unlawful detention on the basis that the decision to detain for the purposes of deportation could not be separated from the decision to deport. Accordingly, if the decision to deport was unlawful, then so inevitably was the decision to detain.
The Claimant had in 2000 been granted refugee status and indefinite leave to remain on the basis of a well founded fear of persecution as a Hutu if he was returned to Rwanda. He was subsequently convicted of a number of offences, the most significant of which was assisting unlawful entry of a non-EEA national (his niece) into the UK. He was subsequently sentenced to 18 months imprisonment.
The decision to detain
Having completed the custodial element of his sentence, the Home Secretary decided to deport him on the basis of article 33(2) of the Refugee Convention which allows the expulsion of refugees "whom there are reasonable grounds for regarding as a danger to the security of the country". It was said that he had been convicted of a "particularly serious crime" and that he "constituted a danger to the community".
The decision was based on section 72(4)(a) of the Nationality, Immigration and Asylum Act 2002, which gave the Home Secretary the power in the Nationality, Immigration and Asylum Act 2002 (Specification of Particularly Serious Crimes) Order 2004 ('the 2004 Order') to specify 'particularly serious offences'. Assisting unlawful immigration to a member state was such a specified offence. The Claimant was accordingly held in immigration detention pending the making of a deportation order.
The Claimant's Challenge
The Claimant unsuccessfully appealed the Home Secretary's decision to the Asylum and Immigration Tribunal. He thereafter sought judicial review of the deportation order on the basis that the 2004 Order was itself ultra vires. He also claimed damages in respect of unlawful detention. In EN (Serbia) v Secretary of State for the Home Department  EWCA Civ 630, the Court of Appeal determined that the 2004 Order was ultra vires the enabling power and was therefore unlawful.
In R (Draga) v Secretary of State for the Home Department  EWCA Civ 842, the Court of Appeal relied on the Supreme Court's decision in R (WL (Congo)) v Secretary of State for the Home Department  1 AC 245 (" Lumba") to hold in essence that the lawfulness of immigration detention was a separate issue to any flaw in the decision to make a deportation order or in the making of the order. This was on the basis that the decision to detain and the decision to deport were separate, and the public law error that had led to the decision to deport did not bear on the decision to detain. The Supreme Court refused permission to appeal the decision in Draga.
The Court of Appeal in DN held itself to be bound by Draga and rejected the Claimant's claim.
The Supreme Court's Decision
Lord Kerr for the majority began by referring back to Lumba, and in particular to the emphasis in Lord Dyson's judgment on the lack of any difference between a detention which is unlawful because there was no statutory power to detain and a detention which is unlawful because the decision to detain was made in breach of a rule of public law. He held at  that:
Here, as in Lumba, there was no lawful statutory power to detain. The statutory power to which recourse had been had in deciding to make the deportation order, and in making it, was invalid. Detention in this instance was for the express purpose of facilitating the deportation. Without the existence of a deportation order, the occasion for (much less the validity of) detention would simply not arise. To divorce the detention from the deportation would be, in my view, artificial and unwarranted.
Lord Kerr held that the making of a deportation order was a two stage process involving (1) notice of a decision to deport and (2) the making of the deportation order. Detention at both stages was "entirely dependent" on the decision to deport as "without that decision the question of detention could not arise, much less be legal." Accordingly, the detention was inevitably "tainted" by public law error and "the principle in Lumba applies with full force and effect to the circumstances of this case."
That principle could only be displaced by a specific rule of law, which did not exist in this case as the existence of a statutory right to appeal did not constitute such a rule. Lord Kerr did not accept the argument made by the Home Secretary that the independent judicial decision embodied in the statutory appeal process 'removed the legal error' and/or break the chain of causation between the decision to deport from the decision to detain. He held that the decision to deport was the prerequisite to the decision to detain — where the deportation to deport was invalid, the unlawfulness of a detention founded upon it was inevitable:
This is not an instance of a series of successive steps, each having, potentially, an independent existence, capable of surviving a break in the "chain". To the contrary, the lawfulness of the detention is always referable back to the legality of the decision to deport. If that is successfully challenged, the edifice on which the detention is founded crumbles.
The clear legal right not to be unlawfully detained could not extinguished by the need for finality in litigation and for legal certainty.
Lord Kerr held that Draga was wrongly decided. Further, in as much as the Court of Appeal's decision in Ullah v Secretary of State for the Home Department  Imm AR 166) suggested that there was a stand alone power to detain where notice of an intention to deport had been served, Ullah too was also wrongly decided:
Absent a lawful basis for the making of a deportation order, it is not possible to breathe legal life into the decision to detain.
The Supreme Court's judgment is an important reminder of the centrality of its earlier decision in Lumba to issues surrounding unlawful detention, and an emphatic statement of the importance of the detention being legally justified and based on lawful decision making.
There is clearly a significant risk of an increased number of successful claims for unlawful detention being brought on the basis that the original decision to deport was unlawful. What remains to be seen is the extent to which there will be a restraint on any compensation payable through the operation of the other limb of Lumba: namely that only nominal damages will be payable if it can be shown that the detention would have been lawfully detained in any event if the (deportation) decision had itself been reached lawfully.