The Foreign Secretary is in danger of misleading the House by his reply to the hon. Member for Sheffield, Heeley (Mr. Michie) that Ministers must sign certificates. The Foreign Secretary is not an automaton and is under no obligation to sign automatically a certificate the minute that someone tells him that it comes within an area that might be covered by public interest immunity. Surely, he has to exercise his judgment as to whether he should claim public interest immunity in the circumstances of each case. There is a particular obligation on him to exercise his discretion when the people involved are in danger of being sent to prison for carrying out the Government's wishes.