Sovereign immunity — Property of foreign States and State-owned agencies — Agreements for construction and financing of enriched uranium factory and nuclear reactors for Iranian State — Repudiation of agreements by new regime in Iran — Action for damages — Conservatory attachment — Conditions for immunity from execution-Attachment of funds representing debts owned to Iranian State in repayment of loan to finance nuclear programme — Whether such funds to be regarded as allocated for a specific commercial activity — Whether absence of specific allocation for any purpose prevents attachment — Whether the production of enriched uranium is a sovereign activity — Waiver — Whether adoption of arbitration rules of the International Chamber of Commerce constitutes waiver — The law of France