State immunity — Jurisdictional immunity — Locally recruited foreign national employed as driver by mission of foreign State — Contract of employment — Claim for wrongful dismissal — Whether foreign State entitled to jurisdictional immunity — Subordinate nature of employment — Whether dismissal of such an employee constituting an act of State — Whether enquiry into lawfulness of dismissal would infringe sovereignty of foreign State — Whether courts entitled to exercise jurisdiction over claim relating to purely financial matters — The law of Switzerland