Bank of Credit and Commerce International (overseas) Ltd v Price Waterhouse [1997] 4 All ER 108

The liquidators of the plaintiff bank commenced actions against the defendants, who were the bank’s former auditors. The defendants sought to bring into the proceedings Abu Dhabi (constituent territory of United Arab Emirates, a recognised state by UK) and issue a 3rd party notice against Sheikh Zayed, Ruler of Abu Dhabi and president of UAE. Sheikh Zayed applied to set aside the notice on the ground that he was immune from suit as a diplomatic agent. The defendants contended that they were bringing proceedings against him in his public capacity as the Ruler and embodiment of Abu Dhabi, and that since the territory was not immune as a separate entity under 14.2 SIA 1978 it had not acted in exercise of sovereign authority of UAE

When a head of a recognised State is acting in his private capacity, he has the same immunities as say, the ambassador [ratione personae (to carry out functions effectively, that is the raison d’etre)] of that state under the 1964 Diplomatic Privileges Act. When acting in his public capacity, as the embodiment of the state, he has all the immunities the state [ratione materiae] has under SIA 1978. The immunities are cumulative.