AC-2024-LON-001145 - [2025] EWHC 2075 (Admin)

It is now well-established that res judicata is a “portmanteau” term used to describe a number of different principles, including issue estoppel and cause of action estoppel (Virgin Atlantic Airways Ltd v Zodiac Seats UK Ltd [2013] UKSC 46, [2014] AC 160, para 17, per Lord Sumption with whom the other members of the court agreed). As set out in Mr Dunlop’s skeleton argument, the Virgin Atlantic case provides an analysis of the principles of res judicata as follows:

I received no written submissions from Mr Ojo on the subject of res judicata. At the outset of his oral submissions, he handed up a copy of R v Secretary of State for the Home Department, Ex parte Momin Ali [1984] 1 WLR 663. In that case, Sir John Donaldson MR expressed the view (at 669H-670B) that the principles of issue estoppel do not apply within public law:

“Just as I think that the doctrine of issue estoppel has, as such, no place in public law and judicial review (see Reg. v. Secretary of State for the Environment, Ex parte Hackney London Borough Council [1983] 1 W.L.R. 524, approved by this court [1984] 1 W.L.R. 592), so I think that the decision in Ladd v. Marshall [1954] 1 W.L.R. 1489 has, as such, no place in that context. However I think that the principles which underlie issue estoppel and the decision in Ladd v. Marshall, namely that there must be finality in litigation, are applicable, subject always to the discretion of the court to depart from them if the wider interests of justice so require” (emphasis added).

Mr Dunlop had not been given proper notice of Momin Ali but drew my attention to a passage of the judgment, at p.670B-D, in which Sir John Donaldson cited earlier authority, as follows:

“I find myself in complete agreement, mutatis mutandis, with the judgment of the Divisional Court, given by Gibson J. in Reg. v. Governor of Pentonville Prison, Ex parte Tarling [1979] 1 W.L.R. 1417, 1422-1423, when he said: ‘First, it is clear to the court that an applicant for habeas corpus is required to put forward on his initial application the whole of the case which is then fairly available to him. He is not free to advance an application on one ground, and to keep back a separate ground of application as a basis for a second or renewed application to the court. The true doctrine of estoppel known as res judicata does not apply to the decision of this court on an application for habeas corpus: . . . There is, however, a wider sense in which the doctrine of res judicata may be applicable, whereby it becomes an abuse of process to raise in subsequent proceedings matters which could, and therefore should, have been litigated in earlier proceedings…’” (emphasis added).

Mr Dunlop also undertook a rapid electronic search for recent cases in which Ex parte Momin Ali had been considered. This led him to R (Tomlinson) v Secretary of State for the Home Department [2025] EWCA Civ 253. In that case, the Court of Appeal considered (among other things) the application of principles of res judicata in the public law context. Giving the lead judgment, Falk LJ (with whom Andrews LJ and Bean LJ agreed) quoted (at para 57) the passage from Ex parte Momin Ali that I have quoted at paragraph 78 above and upon which Mr Ojo relied.

However, Falk LJ referred to a number of other authorities that render the legal position more nuanced than Mr Ojo suggested. In particular, she cited (at para 41) the passage in the speech of Lord Bridge of Harwich in Thrasyvoulou v Secretary of State for the Environment [1990] 2 AC 273 in which he stated that the principles underlying the doctrine of res judicata were not confined to litigation in the private law field but had their place in the criminal law and, in principle, in the field of public law. Falk LJ went on to hold (at para 66) that “Lord Bridge’s statement of principle in Thrasyvoulou is of general application.”