State immunity — Jurisdictional immunity — Employment dispute — Employee of embassy of foreign State-Locally recruited national of receiving State employed in administrative capacity — Claim for unfair dismissal — Whether foreign State entitled to jurisdictional immunity — Restrictive theory of immunity — Whether employment performed jure gestionis or jure imperii — Whether employment activity forming necessary part of functions of diplomatic mission

Relationship of international law and municipal law — Customary international law — Establishment of rules through State practice — State immunity — Restrictive theory of immunity — Scope of rule — The law of Portugal