International organizations — United Nations — Officials — Immunity — Scope — Convention on the Privileges and Immunities of the United Nations, 1946, Article VI, Section 22 — Diplomatic Privileges (United Nations and International Court of Justice) Order 1949, Article 12 — Defamation proceedings — United Nations Special Rapporteur — Whether immune from suit — Whether defendant making alleged defamatory statements in his capacity as Special Rapporteur — Whether certificates issued by Secretary-General of United Nations and Minister of Foreign Affairs conclusive evidence of defendant’s immunity — Role of national courts in questions of immunity

Relationship of international law and municipal law — Treaties — Convention on the Privileges and Immunities of the United Nations, 1946 — Whether defendant immune from legal process — United Nations and Government of Malaysia having different views on question — Section 30 of Convention — United Nations and Government of Malaysia agreeing to refer question to International Court of Justice for Advisory Opinion — Whether Advisory Opinion having binding effect — The law of Malaysia