Alan Johnson's reputation as a good-natured bruiser ready to tackle any fight will be sorely tested in the key role of shadow chancellor.
He had been the most cheerful and unstuffy member of Tony Blair and Gordon Brown's Cabinets, holding a succession of posts from Work and Pensions Secretary to Trade Secretary to Education Secretary, to Health Secretary and finally Home Secretary.
His amiable nature has sometimes belied a tough political operator but it nevertheless ensured his popularity, not merely among all wings of the Labour movement but among his political opponents as well.
He was beaten by Harriet Harman to the party's deputy leadership in 2007, despite being an early favourite, but accepted that defeat with typical good grace.
Alan Arthur Johnson was born on May 17, 1950 and orphaned at an early age. He was virtually brought up by his elder sister.
He was educated at Sloane Grammar school, Chelsea, leaving school at the age of 15 without any qualifications. Johnson stacked shelves at Tesco before becoming a postman in London in 1968, when he also joined the Union of Communication Workers.
Mr Johnson had a brief brush with the Communist Party, but his trade union activity seemed to be his major concern. He was transferred to Slough in Berkshire in 1969 and was elected to the branch committee of the union in 1973 and chairman of the Slough branch in 1976.
He was elected to the National Executive Council of the UCW in 1981 and six years later became a full-time officer of the union, mainly responsible for national negotiations on behalf of the 100,000 postal, delivery and sorting staff.
And in 1982 he became the youngest general secretary in the history of the UCW.
Before entering Parliament in 1997, he served on the general council of the TUC and was a member of the ruling National Executive Committee of the Labour Party.
And when, in 1995, the UCW merged with the National Communication Union, Johnson became joint general secretary.
Johnson was elected Labour MP for Hull West and Hessle in 1997, the year of Blair's first Labour landslide. His maiden speech concerned the problems of trawlermen, saying that in 150 years, Hull had lost 900 boats at sea.
He regularly spoke in the Commons on Post Office issues and on electoral reform, working time, fairness at work, fishermen's compensation and the loss of the trawler "Gaul".
After two stints as a parliamentary private secretary, Johnson was appointed as competition minister at the Department of Trade and Industry in 1999, and the following year became minister of higher education, even though he had himself left school at the age of 15.
After the 2001 General Election, Johnson was appointed minister of state for employment relations and regions, and in the reshuffle two years later he became minister of state for lifelong learning, higher and further education.
He entered the Cabinet in September 2004 as Secretary of State for Work and Pensions, and began his succession of posts in the top ranks of government.
Now he faces the key job of spearheading Labour's opposition to the coalition's cuts programme.