Key takeaways: 

• The recognition of a head of state is an executive prerogative. Where the UK Government has made such a determination, the courts cannot go behind it, in accordance with the “one voice” doctrine. In case of ambiguity, guidance should be sought from the Foreign, Commonwealth and Development Office.
• The act of state doctrine requires that the English courts recognise and not question the effect of foreign executive acts performed within the state’s proper jurisdiction, even if their effects are felt extra-territorially.
• The act of state doctrine does not permit an inquiry into the validity or lawfulness of the executive act under the relevant domestic law. However, where a domestic court has declared the executive act null and void under that law, it is up to the English courts to consider in accordance with ordinary principles whether to recognise the judgment and therefore remove the impugned executive acts from the scope of the act of state doctrine.