Law officer of the Crown
When Churchill regained power in 1951, Manningham-Buller became the Solicitor General for England and Wales and was knighted; in 1954 he was sworn into the Privy Council and became the Attorney General for England and Wales. In 1956 he succeeded his father in his baronetcy.
In 1957, Manningham-Buller prosecuted suspected serial killer Dr John Bodkin Adams for the murder of two elderly widows in Eastbourne, Edith Alice Morrell and Gertrude Hullett. The jury acquitted Adams on the Morrell charge after deliberating for less than an hour. Manningham-Buller controversially entered a nolle prosequi regarding Hullett. Not only was there seemingly little reason to enter it (Adams was not suffering from ill health), but the Hullett charge was deemed by many to be the stronger of the two cases. Mr Justice Patrick Devlin, the presiding judge, in his post-trial book termed Manningham-Buller's act "an abuse of process". Devlin also criticised Manningham-Buller for his uncharacteristic weakness at a crucial moment in the Morrell case: evidence (some nurses' notebooks) that had gone missing from the Director of Public Prosecutions's files, turned up in the hands of the defence on the second day of the trial. Manningham-Buller claimed he had not seen them before but failed to halt their admission as evidence, or ask for time to acquaint himself with their contents. They were subsequently used by the defence to throw doubt on the accuracy of the testimony of various nurses who had worked with Adams and who had questioned his methods and intentions. This damaged the prosecution tremendously, fatally scuppering the case. Manningham-Buller's handling of the case later provoked questions in the House of Commons.
Detective Superintendent Herbert Hannam of Scotland Yard, the chief investigator, suspected political interference due to Manningham-Buller's membership of a government, which had no interest in seeing a doctor hang. Indeed, on 8 November 1956, Manningham-Buller himself had handed a copy of Hannam's 187-page report to the President of the British Medical Association (BMA), effectively the doctors' trade union in Britain. This document – the prosecution's most valuable document – was in the hands of the defence, a situation that led the Home Secretary, Gwilym Lloyd-George, to reprimand Manningham-Buller, stating that such documents should not even be shown to "Parliament or to individual Members". "I can only hope that no harm will result" since "the disclosure of this document is likely to cause me considerable embarrassment". Subsequently, on 28 November 1956, Labour MPs Stephen Swingler and Hugh Delargy gave notice of two questions to be answered in the House of Commons on 3 December regarding Manningham-Buller's contacts with the General Medical Council (GMC) and BMA regarding the Adams case in the previous six months. Manningham-Buller was absent on the day in question but gave a written reply stating he had "had no communications with the General Medical Council within the last six months." He avoided referring to the BMA directly (despite it being named in the questions) and therefore avoided lying, though it could be argued, still deliberately misled the House. Manningham-Buller then proceeded to launch an investigation into how his contact with the BMA had come to be known by the MPs. A leak from Scotland Yard was suspected and Hannam was reprimanded.
Charles Hewett, Hannam's assistant in the investigation, has described how both officers were astounded at Manningham-Buller's decision to charge John Bodkin Adams with the murder of Mrs. Morrell, whose body had been cremated. He believed that there were other cases against the doctor, where traces of drugs had been found in exhumed remains, which were more capable of proof. He also considered that a charge of manslaughter would have been more appropriate in the circumstances. He questioned the decision not to proceed further after Adams' acquittal and he believed that a calculating killer escaped justice as a result. Home Office pathologist Francis Camps suspected Adams of killing 163 patients.
Lady Chatterley's Lover was banned in 1928 but republished in 1960 by Penguin Books. The decision was taken to prosecute Penguin under the new Obscene Publications Act. Bernard Levin criticised the decision thus: "It is surely going to be difficult for the prosecution to find anybody taken seriously by the literary or academic worlds to swear that publication of Lady Chatterley's Lover is not in the public interest as a literary event and that its tendency would be to deprave and corrupt those who might read it." When Manningham-Buller saw this in The Spectator, he cabled Sir Jocelyn Simon, Solicitor-General, saying: "suggest seriously consider spectator 19th Reggie". He then sent a letter stating: "It seems to me a clear contempt of court and the only question is should we start proceedings? My feelings is that we should." Manningham-Buller suggested prosecuting "the proprietors of The Spectator, the editor and Mr Bernard Levin" once the Chatterley trial itself was over. Sir Jocelyn convinced him to reconsider.
