Diplomatic relations — Embassy — Premises — Duties of receiving State — Premises ceasing to be used for purposes of embassy — Change of government in sending State — Members of diplomatic mission declining to serve new government — No appointment of new diplomatic representatives by sending State — Occupation of former embassy premises by squatters — Risk that squatters might acquire title by adverse possession — Secretary of State vesting title to premises in himself — Diplomatic and Consular Premises Act 1987 — Requirement that Secretary of State satisfy himself that action permissible under international law — Role of the courts — Judicial review — Vienna Convention on Diplomatic Relations, 1961 — Whether Secretary of State's action compatible with Convention

Diplomatic relations — Severance — Circumstances amounting to severance — Duties of receiving State regarding premises of mission — Relations between Cambodia and the United Kingdom — Overthrow of Government of Cambodia in 1975 — Cambodian diplomats in London declining to serve new regime — New regime displaced by invasion in 1978 — United Kingdom withdrawing recognition of new regime following invasion — Absence of dealings between United Kingdom and regime installed by invasion — Whether tantamount to severance of diplomatic relations — Vienna Convention on Diplomatic Relations, 1961, Article 45 — Whether applicable to premises formerly used by Cambodian diplomatic mission in London

Governments — Change of government — Effects — Changes of government in Cambodia in 1976 and 1978–9 — Effects on diplomatic representation in the United Kingdom — Withdrawal of recognition of Pol Pot Government by United Kingdom in 1979 — United Kingdom not recognizing or dealing with any rival regime in Cambodia

Recognition — Governments — Withdrawal of recognition — Cambodia — United Kingdom withdrawing recognition of Pol Pot Government without recognizing any other government

Relationship of international law and municipal law — Act of State and justiciability — Whether English courts appropriate forum for resolution of dispute between United Kingdom and foreign State — Diplomatic and Consular Premises Act 1987 — Requirement that Secretary of State satisfy himself that proposed action in accordance with international law — Whether duty of court to determine if action actually compatible with international law — The law of England