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Habeas corpus and the Illegal Migration Act 2023

The Illegal Migration Act 2023 was recently granted royal assent. There is much work to be done in identifying challenges that can be made to the Act, and in identifying the ways in which litigation can be used to mitigate its invidious effects. This piece aims to make a small contribution to that endeavour, specifically in relation to immigration bail, now governed by s.13 of the Act. Contrary to the fears of some commentators, in this post I will suggest that the writ of habeas corpus could potentially experience a revitalisation in this area and fill the lacuna left by the ousting of judicial review under s.13(4) of the Act. 

Concerns raised at drafting stage

In its report on the Illegal Migration Bill (as it then was), the House of Lords Select Committee on the Constitution raised concern at the Bill’s ouster of review of immigration detention at §§11-16. It was noted that what is now section 13(4) contains “a partial ouster clause restricting judicial review during the first 28 days of detention to challenges on the grounds that the Secretary of State has acted “in bad faith” or “in such a procedurally defective way as amounts to a fundamental breach of the principles of natural justice”. The clause therefore severely restricts judicial review over the decision to detain an individual for the first 28 days”, not least by removing judicial review of immigration detention on Hardial Singh [1984] 1 WLR 704 grounds. The mechanism by which this is achieved is by inserting a new paragraph 3A into Schedule 10 to the Immigration Act 2016 (which is not yet in force, see s.68 of the 2023 Act).

Given that this clause found its way into the final version of the Act, the upshot is that judicial review of detention within the first 28 days thereof is severely hampered. The Committee noted at §15 that what is now paragraph 3A(5) of Schedule 10 to the 2016 Act permits an individual in immigration detention to apply for a writ of habeas corpus (in England, Wales or Northern Ireland) or for suspension and liberation (in Scotland). They stated however that:

“these options do not provide the same range of remedies as an application for judicial review—they determine only whether the Secretary of State or immigration officer has the power to detain an individual. Given the wide range of powers to detain in clauses 10 and 11, it is likely to be very rare that a writ of habeas corpus or suspension and liberation will succeed.”

My view is that this latter statement is not quite right. Whilst on its face the case of R v Secretary of State for the Home Department ex p. Cheblak [1991] 1 WLR 890 did appear to restrict the writ of habeas corpus to challenges to the existence of powers (that is, to challenges to jurisdictional errors of law), a close look at the case law would suggest that the writ is also available to challenge errors as to the exercise of such powers, namely as to non-jurisdictional errors. This means that the writ of habeas corpus may be used to challenge immigration detention within the first 28 thereof on Hardial Singh and other grounds, even where judicial review is ousted. 

The procedural primacy of judicial review

The legal advisers to the House of Lords Constitution Committee, Professors Alison Young and Stephen Tierney, published an accompanying piece in which they cited an article I wrote in 2019 as justification for the view that habeas corpus actions are “narrower than actions for judicial review”, such that the lacuna left by the ousting of judicial review in s.13 has not been filled by paragraph 3A(5) of Schedule 10. In its submissions to the Committee, JUSTICE cited my piece as justification for the same view. 

Happily, however, I am not sure that this summary of the law on habeas corpus is correct. No doubt my original piece was not clear, but the point that I intended to make was one about procedural priority: in cases where a judicial review is available, it is that mechanism that is used to offer a remedy, not habeas corpus. This is not to say that the substantive scope of habeas corpus is necessarily narrower than that of judicial review, rather, judicial review is the preferred method by which detention is challenged when such is unlawful on the grounds of a public law error.

In that piece, I cited the leading case of Cheblak in which Lord Donaldson MR stated at at 894C-E that: 

“A writ of habeas corpus will issue where someone is detained without any authority or the purported authority is beyond the powers of the person authorising the detention and so is unlawful.  The remedy of judicial review is available where the decision or action sought to be impugned is within the powers of the person taking it but, due to procedural error, a misappreciation of the law, a failure to take account of relevant matters, a taking account of irrelevant matters or the fundamental unreasonableness of the decision or action, it should never have been taken.  In such a case the decision or action is lawful, unless and until it is set aside by a court of competent jurisdiction.”

In short, Lord Donaldson held that judicial review is concerned with errors taken within jurisdiction, whereas habeas corpus is concerned with errors going to jurisdiction. The interpretation of this that I offered was that “where an administrative or judicial act authorising imprisonment is impugned, the remedy of judicial review takes primacy, unless the error rendering the authorisation unlawful is outside the jurisdiction of the decision-maker” (emphasis added). 

This is an issue of “remedial primacy”: in cases where judicial review is available for detainees, habeas corpus falls behind it in the remedial queue. This is not to say that habeas corpus has nothing to say about errors made within the jurisdiction of decision-makers. As Sir William Wade put it in “Habeas Corpus and Judicial Review” (1997) 113 LQR 55 at 62, the concern of habeas corpus is purely whether “this detention [is] unlawful”. Rather, it is simply that, as a matter of procedure, such errors are rectified pursuant to actions for judicial review rather than for habeas corpus

As such, it is not necessarily the case that the scope of habeas corpus is narrower than that of judicial review of detention decisions. It may well have something to say about detention where such is tainted by a public law error. It is just that it has been prevented from doing so because of the procedural primacy afforded to judicial review up to now. The open question therefore is: where courts are no longer permitted to ask whether detention is unlawful on public law grounds by means of judicial review under the 2023 Act, will they ask that same question by means of the writ of habeas corpus

What happens to habeas corpus when judicial review falls away?

The reality is that the writ of habeas corpus has issued in cases involving non-jurisdictional errors of law in cases both pre- and post-dating Cheblak. Perhaps most importantly, the case of Hardial Singh was itself an action for habeas corpus. Woolf J was comfortable in principle with the court using that writ to order release of Mr Singh after an adjournment of 3 days if the Home Office were not able to show that “the applicant is due to be removed within a very short time indeed”, or that evidence was provided “which reveals a wholly different situation from that indicated by the evidence which is at present before me”, 709C-E. 

As explained by Lord Brown in R (Khadir) v Secretary of State for the Home Department [2005] UKHL 39, [2006] AC 207 at §33: 

“To my mind the Hardial Singh line of cases says everything about the exercise of the power to detain (when properly it can be exercised and when it cannot); nothing about its existence” (emphasis in the original). 

It follows that the writ can issue in cases in which the Hardial Singh principles are breached, even where such is characterised as an error within jurisdiction. Indeed, the writ has issued in cases post-dating Cheblak on Hardial Singh grounds, see for example In re Mahmod (Wafsi Suleman) [1994] EWHC 3 (Admin). 

More generally, the scope of the writ of habeas corpus is not static. It was created as the law’s reaction to the excesses of state power, and its meaning and function has shifted by virtue of iterative common law reasoning over time. The revitalisation of judicial review in the 1960s across the entire spectrum of administrative decision-making meant that the need for habeas corpus fell away in detention cases as a matter of practicality, but that does not mean that its capacity to challenge unlawful detention fell away as a matter of principle. 


It is likely that this question will be litigated sooner rather than later once section 13 comes into force. As immigration and public lawyers, the hope is that the common law rediscovers some of its old resources, and brings habeas corpus back to the fore again.