Born in Prestatyn, North Wales, the son of a white-collar railwayman, the former steward on Cunard passenger liners was an activist during the 1966 strike by the National Union of Seamen.
Known for his short fuse, sometimes directed towards the media, he often seems on the point of breaking out against his more circumspect colleagues from a left position. He is sometimes seen as a left-wing - and more sober - version of the late George Brown.
Popular with loyalist audiences and blunt spoken, his greatest hour recently was his delivery of the 'one member, one vote' reforms for John Smith through a powerful platform speech at last year's Labour party conference.
Far shrewder than his public persona and still-boyish enthusiasm may suggest, he has been erroneously branded as inflexible and old-fashioned.
Yet it was he who successfully persuaded Mr Smith and Neil Kinnock to modify Treasury rules to allow more private sector investment in railways, and who from a union base helped persuade the unions they had to reduce their hold on Labour party elections.
Enemies still say he has a chip on his shoulder, is politically irresponsible and is too much of a rough diamond to be party leader.
Friends say his directness and straight-speaking endear him to many voters, and that he is one of the most assiduous political ambulance-chasers in the business.
He still gives the impression of a politician with feelings in an age of cynicism among both parliamentarians and public.
He is a jazz fan. His wife, Pauline, bears more than a passing resemblance to a younger Joan Collins.