Alan Milburn's departure from government just over a year ago to spend more time with his family was a big political surprise.
Mr Milburn is seen as a leading Blairite
The former health secretary is a leading Blairite and was tipped by some as a future Labour leader.
He was one of the prime minister's most energetic ministers, and was regarded in Westminster as highly ambitious.
There had been speculation that he wanted to leave the health department and move to a new role within the cabinet.
But he quit the government saying he was finding it difficult to balance his political work with raising a young family - he has two sons - in the north east, and he had spent 12 months discussing the situation with his partner, Ruth.
Mr Milburn was born on 27 January 1958 and educated at John Marlay School, Newcastle, and Stokesley comprehensive in Cleveland, before going to read history at Lancaster University.
Born 1958 in Birmingham
Educated at John Morley School, Newcastle and Stokesley Comprehensive
Graduated in history from Lancaster university
Co-ordinator at Trade Union Studies Information Centre
Business development officer, North Tyneside Council 1990-92
MP for Darlington 1992
Opposition treasury spokesman
Chief Secretary to the Treasury 1998
Secretary of State for Health 1999
Raised by a single mother, he cut his political teeth fighting for shipbuilding and steel jobs on Tyneside and a raft of other campaigns.
He worked in a Marxist bookshop called Days of Hope for £20 a week and was a CND activist.
He ran the campaign to save Sunderland's shipyards and is a past president of
the Union for Manufacturing, Science and Finance in the north east.
Mr Milburn decided to join the Labour Party in 1983, becoming MP for Darlington in 1992.
He rose swiftly once Labour came to power in 1997, first as a junior health minister and then, briefly chief secretary to the Treasury.
Mr Milburn in his days as a young radical
He was promoted to become health secretary following Frank Dobson's resignation in 1999.
He had a bruising battle with Mr Brown over the controversial foundation hospitals plan.
The chancellor opposed the moves and Tony Blair had to intervene in the clash between him and Mr Milburn.
And the health secretary took a lot of flak over the proposals, acting as a barrier between Mr Blair and the criticism.
'Passion and humour'
There was concern in the Labour rank and file that the foundation hospital proposals will create a two-tier health service.
Mr Milburn is thought to have spent much of the past 12 months working on ideas for Labour's next election manifesto, further refining the reform agenda he pursued while health secretary.
He has also been an energetic participant in Labour's "big conversation" consultation exercise, travelling the country to talk to activists.
But his return to the back benches appeared to have been cemented when he accepted a £30,000 consultancy with Bridgepoint Capital, an investment firm, a move which drew criticism from some on the left of the party.
Now he is back to play as key role in Labour's general election preparations under the official title of chancellor of the Duchy of Lancaster.