State immunity — Jurisdictional immunity — Employment dispute — Locally recruited employee of foreign embassy — Employee a national of neither sending State nor receiving State — Claim for dismissal — Entitlement of foreign State to immunity — Distinction between sovereign and non-sovereign activities — Distinction between senior and subordinate employees — European Convention on State Immunity, 1972 — Whether Convention rules applicable to non-parties — State practice

Diplomatic relations — Immunity — Embassy technical and administrative staff — Right to institute proceedings in courts of receiving State — Whether authorization of sending State required — National of neither sending nor receiving State — Vienna Convention on Diplomatic Relations, 1961, Article 32(3) Sources of international law — Treaties — European Convention on State Immunity, 1972 — Whether declaratory of existing rules of customary international law — Whether applicable to third States — The law of Switzerland