Sovereign immunity — Absolute theory — Whether may exceptions recognized by English law — Commercial transaction — Whether sovereign immunity applicable — Transaction unconnected with England — Capacity of the English courts to develop exceptions to the general principle of sovereign immunity — Foreign States — Government department succeeding to rights and duties of government-owned corporation — Whether entitled to sovereign immunity — International law in general — Relation to municipal law — Incorporation and transformation doctrines — Doctrine of binding precedent — Whether English courts bound by earlier decisions relating to international law — The law of England