Sovereign immunity — Foreign States and agencies and their property — Agreement for lease of films by television authority of foreign State — Action for breach of agreement — Whether authority entitled to jurisdictional immunity — European Convention on State Immunity, 1972, Articles 1 to 15 — Whether declaratory of existing international law on jurisdictional immunity of States — Acts iure imperii and iure gestionis — Whether nature or purpose of act decisive — Requirement of close connection between case and forum — Attachment of assets — Immunity from attachment — European Convention on State Immunity, 1972, Article 23 — Whether declaratory of existing international law on immunity from enforcement of States — Egyptian Office of Information and Tourism — Whether entitled to immunity from attachment — Whether its assets allocated for the performance of sovereign functions — Relevance of distinction between patrimonial and administrative assets — Whether purpose for which assets are allocated is decisive — The law of Switzerland