State immunity — Jurisdictional immunity — Police authority of foreign State — National of forum State agreeing to sell narcotics to undercover police officer of foreign State — Agreement concluded in forum State — Undercover police officer acting without acquiescence of forum State — Action against foreign State for unlawful entrapment and prosecution — Whether foreign State entitled to immunity — Distinction between sovereign and non-sovereign acts

State responsibility — Acts and omissions of State organs and officials — Duty to provide diplomatic protection to nationals in foreign State — Whether duty existing under customary international law

Jurisdiction — Executive jurisdiction — German police officer engaged in undercover operations in the Netherlands — German authorities failing to obtain consent of the Netherlands

States — Conduct of foreign relations — Attempt to secure repatriation of national held in custody by foreign State — Trial pending for drug trafficking offences — National allegedly unlawfully entrapped into committing offences in foreign State — Proceedings instituted by national against State of nationality requiring it to secure his extradition from foreign State — Whether State under a duty to seek extradition

Sources of international law — Treaties — Relationship between treaties and customary international law — European Convention on State Immunity, 1972 — Whether declaratory of international law — The law of the Netherlands