State immunity — Jurisdictional immunity — Scope — Application to individual officials — Human rights — Universal jurisdiction — Scope of immunity under Convention against Torture and Other Cruel, Inhuman or Degrading Treatment or Punishment, 1984 — Double jeopardy

International organizations — United Nations — Privileges and immunities — Immunity of experts on missions for the United Nations — Waiver of immunity — Convention on the Privileges and Immunities of the United Nations, 1946, Sections 22 and 23 — United Nations and International Court of Justice (Immunities and Privileges) Order 1974 — Whether waiver can be retroactive — Whether waiver needing to be express — The law of England