Hanratty and Another v Lord Butler of Saffron Walden (1971) SJ 382
In 1970 the proposed plaintiffs, parents of H, hanged for murder in April 1962, issued a writ claiming damages for negligence against the 1962 Home Secretary in failing to consider properly new material presented to him after the conviction and the dismissal of an appeal but before sentence had been carried out. The statement of claim stated that the Home Secretary had a duty to investigate the evidence not before the jury which was in his possession prior to his decision not to grant a stay of execution and not to advise Her Majesty to reprieve the convicted man....
LORD DENNING MR said that: H's defence at the trial was an alibi at Liverpool, later changed to Rhyl. After his conviction his solicitors obtained statements from witnesses at Rhyl which were sent to the Home Secretary after H's appeal had been dismissed but before the sentence had been carried out. His parents now sought to bring an action for negligence against the Home Secretary for not looking into the matter properly and claiming that they had his right of action to damages for loss of expectation of life. Even if there were fault or negligence on the part of the Home Secretary, did the law permit an action such as that proposed? No such case appeared in the books and the only colour it could be given was the recent development of the law of negligence, from Donoghue v Slevenson [1932] AC 562, to Dorset Yacht Co Ltd v Home 0fflce [1970] AC 1004; and it was urged that there was sufficient in the proposed action to warrant the court considering it. The high prerogative of mercy was exercised by the monarch on the advice of one of her principal secretaries of state who took full responsibility and advised her with the greatest conscience and care. The law would not inquire into the manner in which that prerogative was exercised. The reason was plain - to enable the Home Secretary to exercise his great responsibility without fear of influence from any quarter or of actions brought thereafter complaining that he did not do it aright. It was part of the public policy which protected judges and advocates from actions being brought against them for things done in the course of their office. It was a pity that the allegations had been made; but though the court had for the purpose of the present proceedings to assume that they were true, his lordship was satisfied that it was not a matter giving rise to any cause of action in the courts....
SALMON LJ (concurring) said that: No action for negligence could succeed unless it were shown that the negligence caused damage. The only damage that could be alleged here was that but for the negligence of the then Home Secretary the crown would have exercised its prerogative of mercy differently. So if the action were allowed to continue the courts would have to pronounce on the crown's exercise of its prerogative, something which they would not and could not do....