Diplomatic relations — Diplomatic personnel — Immunities and privileges — Entitlement to immunity — Whether requirement that person claiming immunity be a member of the staff of an embassy — Appointment as Ambassador-at-Large — New York Convention on Special Missions, 1969 — Whether reflecting customary law — Whether State not party to Convention obliged to accept status of Ambassador-at-Large — Whether immunity dependent upon notification to receiving State — Whether dependent upon agrément of receiving State — Vienna Convention on Diplomatic Relations, 1961, Article 39 — Whether declaratory of customary international law — Whether attitudes to diplomatic immunity changed since 1961

Relationship of international law and municipal law — Treaties — Effect in municipal law — Vienna Convention on Diplomatic Relations, 1961 — Effect in English law — Diplomatic Privileges Act 1964 — Distinction between articles of Convention incorporated into English law by Schedule to Act and those not so incorporated

Relationship of international law and municipal law — Foreign relations questions before municipal courts — Evidence — Foreign Office certificate — Entitlement to diplomatic immunity — Certificate conclusive of questions of fact — Whether binding on matters of law — Whether exclusive — Whether Secretary of State may submit other evidence to Court

Sources of international law — Treaties — Relationship between treaties and customary international law — Whether provisions in treaty declaratory of custom — Vienna Convention on Diplomatic Relations, 1961 — New York Convention on Special Missions, 1969 — The law of England