State immunity — Head of State — Constituent territory of federal State — Ruler of constituent territory — Whether entitled to immunities and privileges of Head of State — Exemption from immigration control — Certificate from Foreign and Commonwealth Office — State Immunity Act 1978

Recognition — States — Governments — Head of State — Claim by ruler of constituent territory of federal State to privileges and immunities of Head of State — Whether territory recognized as a State

Relationship of international law and municipal law — Recognition of States and Head of State — Role of Executive and courts — Whether certificate from Executive conclusive — The law of England