Convention on Special Missions

The Convention on Special Missions was adopted by the UN General Assembly on 8 December 1969 and opened for signature in New York. It entered into force on 21 June 1985 after reaching the required 22 ratifications. The Convention fills a gap left by the Vienna Convention on Diplomatic Relations (1961) and the Vienna Convention on Consular Relations (1963), which govern permanent missions but not ad hoc diplomacy.

A "special mission" is defined in Article 1(a) as a temporary mission, representing the state, sent by one state to another with the consent of the latter for the purpose of dealing with it on specific questions or performing a specific task. Such missions are common for treaty negotiations, royal or presidential visits, condolence delegations, and technical talks.

Key provisions include:

• Article 8: the sending state must inform the receiving state of the size and composition of the mission.
• Articles 25–28: inviolability of mission premises, archives, and documents.
• Article 29: inviolability of the persons of representatives — they may not be arrested or detained.
• Article 31: immunity from criminal jurisdiction, and broad (though not absolute) immunity from civil and administrative jurisdiction.
• Article 21: the Head of State leading a special mission enjoys the facilities, privileges, and immunities accorded by international law to Heads of State on official visits.

Ratification remains relatively limited compared to the Vienna Conventions — around 40 states parties — and major powers including the United States, France, and China are not parties. Nonetheless, several of its provisions, particularly on personal inviolability and immunity ratione personae for senior officials on mission, are widely regarded as reflecting customary international law. The UK Supreme Court in Freedom and Justice Party v Secretary of State (2018) addressed this customary status in the context of an Egyptian general visiting London.