He was in charge of the Overseas Food Corporation during the disastrous Tanganyika groundnut scheme in the late 1940s; later he became a Labour Party Member of Parliament where he pioneered attempts to outlaw racial discrimination.
He was educated at Tottenham Grammar School in North London, and first worked on the managerial staff of the Daily Herald from 1919.
Plummer left the Daily Express when he was named by John Strachey as chairman-designate of the Overseas Food Corporation at the end of 1947.
[10] Plummer was criticised in an editorial in The Times for "failing to restore confidence (even among his staff) in the higher conduct of the scheme".
[12] The next month, Plummer was also criticised by the Conservatives for giving a contract for air transport to the nationalised British Overseas Airways Corporation rather than two private airlines which had submitted lower tenders, one of whom subsequently went out of business.
[13] A House of Lords debate on the groundnut scheme on 14 December 1949 resulted in a vote of censure of the government, after the Marquess of Salisbury attacked Plummer for being an entirely inappropriate choice to run it.
Plummer responded by saying that all his money was invested in a 900-acre (4 km²) farm in Essex and that although he despised the capitalist system, he had been "extremely fortunate under it and benefited from it".
[25] During the 1955 general election campaign, Plummer was embarrassed when he turned up to give a speech in Hemel Hempstead to find that the caretaker had not unlocked the hall.
[28] In November 1957 Plummer caused uproar on the Conservative benches of the House of Commons by accusing the government of leaking changes to the Bank of England interest rate to the Daily Telegraph and Financial Times.
In August 1960 it was revealed that Plummer had received threatening phone calls and eventually a death threat in a letter from the "Adolf Hitler Memorial League".
and accused him of "[coming] down solidly on the side of coloured spivs and their vice dens as opposed to the white people of Deptford".
[35] He was forced to apologise to Sir Robert Grimston, a Deputy Speaker, when he wrongly accused him of joining a pressure group for commercial radio.