New Labour's outrider returns to the saddle after his surprise jump

When Alan Milburn resigned as Health Secretary last year to spend more time with his family, the political world was stunned. In the corridors of Westminster few could believe the slick, ambitious figure who had aggressively championed public service reform as a rising cabinet star could simply pack it in.

When Alan Milburn resigned as Health Secretary last year to spend more time with his family, the political world was stunned. In the corridors of Westminster few could believe the slick, ambitious figure who had aggressively championed public service reform as a rising cabinet star could simply pack it in.

Only days before he left the Government, Mr Milburn was being tipped for promotion, regarded by many as a potential successor to Mr Blair.

In his resignation letter to Tony Blair he said: "I have already missed a good bit of my children growing up, and I don't want to miss any more." And as recently as May he was declaring life to be "a million times better" outside the Government.

When he gave interviews about a speech proposing that men and women take up to a year off work after the birth of a child, he spoke as he walked in a park with his two sons.

Yesterday he gave up his new life and returned to the Government fold.

Leaving the Cabinet may have given him more time with his partner, Ruth Briel, and his sons but few believed it would entirely remove him from the influential frontline of Labour thinking.

Mr Milburn, 46, has become an "outrider" for the New Labour project. He has called for flexible working for parents, proposed legislation forcing food companies to cut the fat, sugar and salt in their products and called for a greater role for the voluntary sector in public services.

In a speech last November, he gave a taste of the campaigning style which has endeared him to Mr Blair and is liable to make his relations with the Chancellor, Gordon Brown, so difficult. He declared at the time that further decentralisation of decisions was not merely privatisation by another name: "I say we have not gone far enough and need to go further."

Mr Milburn has spoken of the need for Labour to go through another "clause four moment", echoing Tony Blair's battle to reform the party's commitment to state ownership. His new mantra is the need to devolve decision-making to the people. He has also spoken of a three point plan: extending home ownership, creating Scandinavian-style child care and extending choice in public services.

He rallied behind Mr Blair over his decision to bow to calls for a referendum on the European constitution, is said to see the Prime Minister regularly and has been advising him on the next election manifesto.

Mr Milburn has completed a political journey from the hard left to Labour's modernising cutting edge. He was born in January 1958, the son of a single mother in County Durham. He attended John Marlay school in Newcastle, and Stokesley comprehensive in Cleveland, before taking a BA in history at Lancaster University for his BA in history. He did not complete a PhD at Newcastle University on 18th-century radicalism in the North-east.

He got a job as a sales assistant at a Marxist bookshop, Days of Hope, known locally as Haze of Dope, and backed causes such as the Campaign for Nuclear Disarmament and the battle to save Sunderland's shipworkers.

He entered Parliament in 1992 as MP for Darlington and joined the Cabinet as Chief Secretary to the Treasury in 1998, the year after Labour came to power, and was appointed Health Secretary in 1999. His conflicts with Mr Brown also heighten the sensitivity of his appointment.

He championed the cause of foundation hospitals and their freedom from Treasury borrowing rule. The issue provoked a public spat with the Chancellor which rumbled through the Labour party conference two years ago.

The delays in yesterday's announcement of his return suggest he fought hard to secure a powerful role within the Government. But his identification as a fierce debater and advocate for the Blairite wing of the party has made Mr Milburn a controversial figure.

His proposals for public private partnerships in health also antagonised the public sector unions, another factor that led to consternation on the left when reports suggesting that he might return to the Cabinet surfaced over the past few days.

Mr Blair will be gambling that his loyal friend's new job will not push them too far.