State immunity — Jurisdictional immunity — Employment — Foreign military base — United Kingdom national employed as civilian computer operator on United States military base in United Kingdom — State Immunity Act 1978 — Whether Section 16(2) applicable — Whether doctrine of restrictive immunity applicable under common law — Whether act de jure imperii or de jure gestionis — Whether contract kind that private individual could enter into — Whether performance of contract involving both parties in public functions of foreign State — Nature of breach of contract or other act of foreign State giving rise to proceedings — Whether investigation of claim involving investigation into public or sovereign acts of foreign State — Whether respondent entitled to immunity — The law of England