As his father, who by this time was unemployed, could not afford to support him through university, Mulley instead became an accounts clerk under the national health insurance scheme.

[2] At the end of the war, Mulley received an adult scholarship to Christ Church, Oxford, graduating with a first-class degree in politics, philosophy and economics in 1947.

Mulley had been a member of the Labour Party and the National Association of Clerks and Administrative Workers since 1936,[1] and at the 1945 general election he unsuccessfully contested the constituency of Sutton Coldfield.

He became Member of Parliament for Sheffield Park in 1950, a position he held until deselected by his local party prior to the 1983 general election, when his constituency disappeared in a redistribution of boundaries.

[1] After retiring from the House of Commons in 1983, he was created a life peer as Baron Mulley, of Manor Park in the City of Sheffield on 30 January 1984,[4] and he held a variety of directorial positions.