State immunity — Jurisdictional immunity — Customary law obligation to accord immunity — Acta jure imperii and acta jure gestionis — Civil action against State in respect of war crimes and crimes against humanity — Acts having status of acta jure imperii — Territorial tort exception to immunity — Whether applicable to acts of armed forces in conduct of armed conflict — Whether immunity set aside in case of grave illegalities — Jus cogens — Whether immunity available where State accused of violation of jus cogens — Relationship between rule of law violated and rule of law according immunity — Entitlement to immunity determined by law in force at the time action brought — Whether absence of alternative remedy relevant to immunity

State immunity — Procedure — Service of process upon defendant State — Whether immunity of State from jurisdiction precluding service — Service through diplomatic channels

Sources of international law — Customary international law — State practice and opinio juris — Customary law on State immunity — Relevance of national court decisions and legislation — United Nations Convention on the Jurisdictional Immunities of States and Their Property, 2004 — Relevance to customary international law

War and armed conflict — War crimes — Crimes against humanity — Occupied territory — Civilian population — Murder and deportation — The law of Poland