Law officer

He briefly held office as parliamentary secretary to the minister of works in Churchill's caretaker government (May–July 1945) but it was in opposition between 1945 and 1951 that he established himself as a hard-working and valuable MP, becoming chairman of the party's legal committee. His career at the bar also prospered and he took silk in August 1946. Nevertheless, there was some surprise when Churchill appointed him solicitor-general at the formation of the Conservative government in November 1951. Doubts were soon stilled, as Manningham-Buller proved an efficient and successful minister, his achievements stemming more from sheer hard work than from an outstanding intellect. He was a tough and effective debater, though his abrasive style never really endeared him to the House of Commons, even on his own side of the chamber. To many he was best summed up by the nickname of Sir Reginald Bullying-Manner. The Labour MP Tony Benn recalled an appearance before the Commons privileges committee at which Manningham-Buller 'bullied and hacked at me as if I was a man who had been caught red-handed in the act of rape and was then pleading mistaken identity. He really behaved in a most unpleasant and hostile way' (R. Winstone, ed., Tony Benn, Years of Hope, 1994, 368).

In government, on the other hand, Manningham-Buller's work was appreciated and in Churchill's reshuffle of October 1954 he was promoted to attorney-general. There he was prominent in the tribunal of enquiry set up in November 1957 into alleged leaks of information about an increase in the bank rate. Earlier that year he led for the prosecution at the trial of Dr John Bodkin Adams who was accused of murdering an elderly woman patient. After retiring for less than three-quarters of an hour the jury returned a verdict of not guilty—an outcome which damaged Manningham-Buller's standing in parliament and further afield. It may also have played a part in blocking his elevation, upon the retirement of Lord Goddard in September 1958, to the lord chief justiceship, an appointment to which an incumbent attorney-general had hitherto been thought to have first claim. A leading article in The Times on 29 May 1958, which declared that appointment to the chief justiceship should not be regarded as 'some political plum', was widely believed to have been directed at Manningham-Buller's claims. For all that, government colleagues saw him as the very model of a law officer. Harold Macmillan particularly appreciated his handling in parliament in 1959 of the Devlin report into the deaths while under detention of Mau Mau guerrillas in Nyasaland.

Lord chancellor and law lord

It was some indication of his competence that Manningham-Buller served for ten years and nine months under three different prime ministers before finally succeeding Kilmuir as lord chancellor after Macmillan's radical reshaping of his cabinet in July 1962, the celebrated ‘night of the long knives’. Having succeeded his father as fourth baronet in 1956, Manningham-Buller now took the title of Baron Dilhorne of Towcester in the county of Northampton and received the great seal on 16 July. Though it is doubtful whether his appointment helped Macmillan to realize his declared intention of rejuvenating the image of his government—Dilhorne was a less politically prominent figure than his predecessor had been—the new lord chancellor's two years in office were dominated by his political rather than by his legal responsibilities.

At the end of May 1963 the prime minister asked Dilhorne to conduct an investigation into allegations concerning the relationship between John Profumo, secretary of state for war, and Christine Keeler, a society prostitute. After little over a fortnight the lord chancellor told the cabinet that from the security point of view no further enquiry was necessary. But it was his role in the emergence of Macmillan's successor as prime minister that probably represents the most controversial moment of his career. The premier was taken ill shortly before the Conservative Party conference opened in Blackpool in October 1963, and decided to resign. Dilhorne was charged by Macmillan with sounding out the views of cabinet ministers about the succession, a task he performed, according to R. A. Butler, 'like a large Clumber spaniel sniffing the bottom of the hedgerows' (DNB). The lord chancellor began his enquiries at Blackpool and continued them in London the following week. Ministers were summoned to meet him in his small bedroom at the Imperial Hotel. As one recalled,

there was a touch of incongruous farce about sitting on the Lord Chancellor's unmade bed, while he, his massive frame poised in a creaking wooden chair, made a note of the view of a Cabinet Minister as to who should be Prime Minister of England.

Boyd-Carpenter, 175–6

Yet in carrying out his task Dilhorne may have found it difficult to separate the roles of committed partisan and impartial recorder of others' opinions. He himself began by favouring the claims of Lord Hailsham but was alienated by the latter's over-exuberant conference performance and, like Macmillan, transferred his allegiance to the foreign secretary, Lord Home. In the event Dilhorne reported that at least half the cabinet favoured Home, a figure which seems inherently improbable, given the known preferences of several of those polled. A charitable interpretation is that Dilhorne reached the questionable conclusion of preponderant positive support for Home on the basis of an absence of outright hostility towards him on the part of most members of Macmillan's cabinet. If true, this was a curious error for a trained lawyer to make; rumours persisted, which the lord chancellor did little to contradict, that he had deliberately misled the prime minister about the preferences of his cabinet colleagues. Such an interpretation was strengthened by Dilhorne's refusal of requests from senior ministers to convene a cabinet meeting to discuss the whole question of the leadership.

Dilhorne remained in office under Sir Alec Douglas-Home, as Lord Home now became, but his occupancy of the woolsack came to an end when the Conservative government lost the general election of 1964. He was made a viscount in the dissolution honours list. He now became deputy leader of the opposition in the House of Lords, and retained this post when Edward Heath succeeded Douglas-Home as Conservative leader in August 1965, but he left the shadow cabinet without acrimony after the general election of the following year. Though he sat on a Conservative constitutional committee to consider Scottish devolution, which reported early in 1970 with a recommendation for a directly elected Scottish assembly, Dilhorne's time was now devoted largely to the law, and in 1969 he gratefully accepted an offer from Harold Wilson's Labour government to become a lord of appeal in ordinary. In this position he proved by common consent a considerable success and he worked diligently until his retirement at the age of seventy-five in 1980. As a law lord he sat in no fewer than 205 appeals. He was also treasurer of the Inner Temple in 1975.

Dilhorne was not in the highest flight of English lawyers and his tenure of the woolsack was not a period of conspicuous reform. He was out of sympathy with much of the changing mood of the 1960s, opposing the abolition of the death penalty and the legalization of homosexuality. By contrast, he was in favour of majority verdicts and the abolition of the practice of cautioning suspected offenders. He believed that courts should retain their discretion over the question of sentencing but was concerned by the variations in sentences handed down by magistrates' courts and tried to ensure that newly appointed JPs should be subjected to a course of compulsory training. His reputation was badly tarnished by the unusual decision of Lord Devlin, the presiding judge, to publish an account of the Bodkin Adams trial in 1985. From this he emerged as a heavy-handed and unimaginative lawyer who scarcely merited the high offices he had attained. According to Devlin, 'what was almost unique about him and makes his career so fascinating is that what the ordinary careerist achieves by making himself agreeable, falsely or otherwise, Reggie achieved by making himself disagreeable' (Devlin, 39). Such attacks provoked statements of support for Dilhorne from distinguished jurists, including lords Scarman and Bridge. In his public life Dilhorne evoked more respect than affection, but those who knew him more intimately recognized a kindly man, devoted to his family.

Dilhorne died suddenly at Knoydart, Inverness-shire, on 7 September 1980, only a month after his retirement as a law lord. He was buried at the parish church of Deene in Northamptonshire.