International Court of Justice — Advisory jurisdiction — Effect of advisory opinions — Issue before the Court not a dispute — Advisory opinions on legal questions not binding — Consent of States not required for jurisdiction — Convention on the Privileges and Immunities of the United Nations, 1946, Article VI, Section 22 — Applicability to an expert performing mission for United Nations within his State of nationality

International organizations — Officials — Status — Whether special rapporteur is expert on mission under Article VI, Section 22, of the Convention on Privileges and Immunities of the United Nations, 1946 — Whether eligible for immunity in State of nationality — Whether immunity subsists until mission concluded Treaties — Application — Convention on the Privileges and Immunities of the United Nations, 1946 — Interpretation — Definition of “mission” for purposes of Article VI, Section 22, of the Convention — Whether immunity of expert on mission applicable in State of nationality — Effect of reservations