David Miliband: From policy master to class warrior in one leap

What makes David Miliband's meteoric propulsion into the middle ranks of government as schools minister at 36 especially extraordinary – and for at least some older MPs highly irritating – is that he might not even be an MP if Tony Blair had not decided to postpone the 2001 election for a month because of foot-and-mouth.

Having headed Tony Blair's Policy Unit for the seven long years since Blair became Labour leader, he had thought it was time to move on; he had told friends vaguely that he would like to have a crack at "running something" outside mainstream politics after the election and hadn't thought that seriously about being an MP. But suddenly there was time; the manifesto, of which Miliband was the principal author, was finished and there was nothing much to do for a few weeks. The last-minute retirals by ageing MPs were under way, including that of David Clark, the MP for South Shields. Miliband discussed the possibilities with several people at Number 10, including, of course, Tony Blair.

But it was a Policy Unit colleague who finally persuaded him by telling him it would be "great adventure". Though not necessarily a careerist one. Bruce Grocott, Blair's former Parliamentary Private Secretary, warned him sternly: "Only become an MP if you really want to become an MP, representing the people in your constituency, and not as a stepping stone for something else." Unlike many policy wonks, he's a natural speaker; he seems to have had little trouble persuading 183 of the 250 members assembled at the the town's Bolingbroke Hall to vote for him over the two rival candidates.

Thanks to last week's reshuffle, Miliband has had an almost unprecedentedly short time to show he had passed the Grocott test; but all the evidence is that he has done so handsomely. He has immersed himself in the constituency – as early as the election campaign itself the writer Valerie Grove found his unfeigned pride in South Shields amply reciprocated; metropolitan he may be, but that hadn't stopped him absorbing every salient fact about the town, winning over the oldest party member, an ex-suffragette called Ella Roberts, and even doing a spot of line dancing at the local Whiteleas Hall.

He didn't remotely expect to figure in the reshuffle at all let alone as a minister of state. The only hint that his career might be on the move was that Tony Blair put him last year on a group chaired by Guy Verhofstadt, the Belgian Prime Minister, on the future of Europe – at which Miliband had to hold his own among prime and foreign ministers. But that's hindsight. When Alastair Campbell phoned him as a friend to warn him to stay by his phone in London the following day, he had been on his way, as usual, to South Shields.

He may not have the obvious family background to represent a working-class constituency in the North-east whose political traditions were built on mines, docks and shipbuilding. But his background could hardly be richer, spanning the whole turbulent history of 20th-century Europe. You can't fully understand David Miliband or his younger brother Ed, who, as special adviser to the Chancellor, is one of Gordon Brown's closest lieutenants, without knowing something of Ralph Miliband, one of the most influential socialist thinkers of the 20th century.

Brought up in Belgium, Ralph joined Hashomer Hatzair, the Jewish/socialist Young Guard, at the age of 15 in the aftermath of Hitler's rise and the Spanish Civil War. He was lent a copy of the Communist Manifesto by a close friend later hanged at Auschwitz. A year later, he walked with his father to Ostend as the German armies were rolling into Belgium and boarded the last boat to Dover, arriving in London in May 1940. As his English improved, he fell under the spell of Harold Laski, the left-wing academic and Labour Party intellectual, first through his books and later through his teaching, when Ralph became a student at the LSE – a period interrupted by three years' war service as a naval rating and NCO in the Belgian section of the Royal Navy. He then embarked on a long and distinguished teaching career of his own in the US and in Britain, at the LSE and Leeds University.

Because of his father's peripatetic academic life, by the time David arrived at his north London comprehensive, Haverstock, in Chalk Farm, he had already been to four other schools: Primrose Hill Primary – where he was a fellow-pupil of the film director Sam Mendes – Horsforth Newlades Primary and Benton Park in Leeds, and a junior high in Boston, Mass, while his father was teaching at Brandeis.

In his first big speech this week – characteristically he chose to make his initial public pronouncement to the National Association of Head Teachers conference in Torquay rather than accept the welter of interview bids – he said something Tony Blair never could: "I am here today because of state education. My primary school wholly failed to convince me that there was anything more to life than football but it did prove to me there were other things to read about."

Clever, and from a highly intellectual family, he was saved from nerdiness by his passion for sport. He is not only an Arsenal season ticket holder but still plays as a central defender as well as running three times a week. Looking even younger than he is – "like a year eight in a suit" as one delegate to the heads' conference put it a little unfairly on Thursday – he played football and cricket for Corpus Christi, his Oxford college, where he was active in the university Labour club and president of his college's junior common room and took a first in politics, philosophy and economics before going to Massachusetts Institute of Technology to take a master's degree.

Though a voracious reader, he isn't the sort of man who spends Saturday night discussing local government finance. He cooks and entertains. He is married to Louise Shackelton, a violinist in the London Symphony Orchestra (he himself is tone deaf); the couple first met in an aeroplane, chatting across the aisle on a Rome-to-London flight.

"Improbably perfect" in the words of one former colleague, he is notable for having few if any personal or political enemies – a testament to the tact with which he helped to drive through policy in the first term without alienating ministers and their departments. A fairly visceral understanding, not universal in Number 10, of how the Labour Party worked – first honed by his secretaryship of the John Smith-established Social Justice Commission – also helped. His closeness to his brother has survived all the famous tensions of the Brown-Blair relationship Ed has lived for some years above the book-packed flat his brother and sister-in-law share near Primrose Hill.

The sense of inquiry he mentioned on Thursday in his Torquay speech, underpinned by a strong childhood sense of family security, was also in the genes. Poignantly, David and Ed read the draft of, and suggested amendments to, Ralph's last book, Socialism for a Sceptical Age, as its author lay dying in hospital. At the same time David was completing Reinventing the Left, the decisively revisionist 1994 book he edited, to which Gordon Brown contributed and which played a big part in setting an intellectual and ideological framework for New Labour. Asked, as he often is, to explain the contrast between his father's views and his own – which see capitalism as something to be harnessed and regulated rather than ended – he is apt to point to the spectacular differences between the moments at which they came of age. His father was 21 in 1945, David became 21 in 1986 in the midst of the Thatcher-Reagan era when communism was on the brink of collapse. Both men were creatures of their times.

For Miliband's modernising instincts are not in doubt. His "surprisingly well received" message to the headmasters on Thursday was an uncompromising call for further education reform. And while he was on disarming form, the heads are likely to find him a tough opponent if they carry out their threat to take industrial action. As in education, so in wider politics. In a striking article in the current issue of Renewal, he quotes with approval Eduard Bernstein's dictum that "it is a hallmark of revisionism that revisionism never stops" before going on to remind Labour, as one of the key outsiders in Blair's drive to change the public services, that "the charge come election day is always that reform has been insufficient, never that it has been too sweeping or too radical".

His passion about education, at least, is powerfully egalitarian. As a genuine comprehensivist, he has been fiercely eloquent about the poverty of educational chances for children in South Shields. Nor does he think these problems can be solved without money. In the same Renewal article, and in more detail in an earlier little-noticed TES article in April, he floats a radical – in the best sense of the word – proposal "to give some of the poorest children the resources spent in private schools and see how much difference this can make".

If he had a fault at Number 10, it was that he was almost too much of the loyal civil servant. He isn't naive; but untypically among top New Labour types, he never briefed on his own behalf or drew out the differences between competing views in a way that might promote his own. But as a minister this will be different; he will be more exposed; and he will no doubt have to find some of the darker political arts that he has so far eschewed.

He is acutely conscious that political images are built up only to be knocked down. Because of his brains and charm, "in a sense his biggest problem is that he has no problems", asserts one friend. Which means that plenty of people, inside and outside education, will now try to find some. Recently he was especially proud to play football for a Parliamentarians XI at Newcastle's St James' Park, only to put in an own goal at the Gallowgate End. It was a reminder that things don't always go smoothly; and not just in football. But provided he can avoid, as he has notably done so far, too many own goals in his working life he is now on a trajectory that could, in time, take him all the way to the top of the political premiership.

Life story

Born: David Wright Miliband, 15 July 1965, elder son of Ralph Miliband, Marxist political theorist, and Marion; younger brother Ed is political adviser to Chancellor Gordon Brown.

Family: Married Louise Shackelton, a cellist, in 1998.

Education: Attended Haverstock comprehensive in Chalk Farm, north London ("could not overcome my weakness in A-level physics, but it gave me a good start in life"); Corpus Christi College, Oxford (where he gained a first-class degree in philosophy, politics and economics); Kennedy scholar, Massachusetts Institute of Technology.

Policy work: Research Fellow, Institute of Public Policy Research (shared an office with Patricia Hewitt, now Secretary of State for Trade and Industry), 1989-94, including a stint as secretary to John Smith's Commission on Social Justice; head of policy for Tony Blair as Leader of the Opposition, 1994-97; acting head (1997) and then head (1998-2001) of the Number 10 Policy Unit.

Political career: Member of Parliament for South Shields, since 2001 (he was selected as Labour candidate for this safe seat 25 days before the election); appointed Minister of State at Department for Education and Skills, 29 May 2002.

He says: "It's the Third Way between having your cake and eating it."

They say: "He was parachuted into his constituency and has won his ministerial job over people who have slogged for years" – Tam Dalyell, Labour MP