Introduction: the plea of act of state

If, as was suggested in Chapter 6, the true explanation for those cases where non-justiciability is upheld is simply that they disclose no cause of action under municipal law, there remains a much larger set of cases where the plaintiff does have such a cause of action against the state. The question, then, is whether, and, if so, to what extent, the fact that the act of the state is committed in exercise of the foreign affairs or defence power outside the territory of the state can either exclude the claim from the jurisdiction of the courts or constitute a good defence.

In the modern law, this question may arise either in the course of an ordinary claim for civil liability, brought against the Crown pursuant to the Crown Proceedings Acts (the subject of the present chapter); or, where the liberty of the person is involved, by way of the ancient writ of habeas corpus (Chapter 8, part A); or, more generally, by way of a claim for infringement of human rights vouchsafed under domestic human rights statutes (Chapter 8, parts B-D).