Political career
Mayhew was elected to Parliament for the constituency of South Norfolk in the general election of 1945.
In 1945, Mayhew became Under-Secretary of State at the Foreign Office, where he served under Ernest Bevin. According to a long time associate, Claud Morris, Mayhew had "ghost-written some of the most powerful speeches of Ernest Bevin'. He lobbied Bevin and Clement Attlee for a "propaganda counter-offensive" against the Soviet Union. That led in 1948 to the establishment of the Information Research Department (IRD). Mayhew was the first head of the IRD. The department's existence was made public only in 1978, two years after it had closed. Mayhew lost his seat in 1950, but soon returned to Parliament after the death of Bevin, when he won the by-election in 1951 for Bevin's seat of Woolwich East.
During Labour's 13 years in opposition, from 1951 to 1964, Mayhew represented the Labour Party on television, both as a commentator on the BBC and as a presenter on Party Political Broadcasts. He introduced the first Labour broadcast, in 1951, in which he talked with Sir Hartley Shawcross. Mayhew became known as one of the fiercest opponents of unilateral nuclear disarmament in the Labour Party. He also served as Shadow War Secretary from 1960 to 1961 and as a spokesman on foreign affairs from 1961 to 1964.
When Labour took office in 1964, Mayhew was appointed as Minister of Defence for the Royal Navy. However, in 1966, after Harold Wilson's government decided to shift British airpower from carrier-based planes to land-based planes and to cancel the CVA-01 aircraft carrier programme, Mayhew resigned, along with First Sea Lord Sir David Luce.
On 17 December 1969, the Admiralty Board issued a written answer to a question from Mayhew: "The Admiralty Board concludes that the rum issue is no longer compatible with the high standards of efficiency required now that the individual's tasks in ships are concerned with complex, and often delicate, machinery and systems on the correct functioning of which people's lives may depend". This led to a debate in the House of Commons on the evening of 28 January 1970, now referred to as the "Great Rum Debate", started by James Wellbeloved, MP for Erith and Crayford, who believed that the ration should not be removed. The debate lasted an hour and 15 minutes and closed at 10:29 p.m., with a decision that the rum ration was no longer appropriate.
In 1970, Admiral Peter Hill-Norton abolished the rum ration as he felt it could have led to sailors being less capable to manage complex machinery. The last rum ration was on 31 July 1970 and became known as "Black Tot Day", as sailors were unhappy about the loss of the rum ration.
