Sex was her secret weapon

Margaret Thatcher: vol 1, the grocer's daughter by John Campbell (Jonathan Cape, £25, 512pp)

Just before Christmas 1944, 19-year-old Margaret Roberts shared a bed for the night with her Oxford contemporary, Sheila Browne. Their paths were to cross again, more than quarter of a century later, when Margaret Thatcher was Secretary of State for Education and Sheila (still) Browne a Chief Inspector of Schools - en route for the headship of Newnham College in Cambridge.

Their youthful encounter is as fascinating as it was innocent. Innocent, because they were overnighting at the Corby Glen home of another Oxford contemporary, Margaret Goodrich, at the end of her 21st birthday party. But fascinating, because it was to a late-night cocoa-drinking group in the kitchen that Margaret Roberts then first proclaimed her ambition to become a Member of Parliament.

And all the more interesting because of the gusto with which John Campbell dissects half a dozen different accounts of the occasion - four from Margaret herself. He thus disposes of the "romantic and disingenuous story" that the idea never crossed her mind until the end of her time at Oxford - and usefully illustrates, he says a little harshly, a "tendency to embroider her memoirs".

But this is anything but an unsympathetic account of Margaret Thatcher's life to 1979. And rightly so. For although this is a thriller of which we know the end, we are in Campbell's words, "still coming to terms with... the transformation of British politics and society that she wrought - or presided over". And we wonder still, despite all that has been written by and about her, what on earth can have fired and sustained this woman's astonishing yet determined rise to power. To those questions, this searching and beautifully written volume offers the most interesting answers so far.

How far was Margaret Thatcher, as she would have us believe, the naturally political offspring of father Alfred's mayoral background? And how far driven, as Campbell implies, by a settled determination to escape from the austerity of a home without love? She saw very little of either parent thereafter.

Yet her Oxford life was built, from the beginning, on her hyper-active membership of the Conservative Association and the Wesley Society - the very things her father might have wished for her. She was indeed "a preacher before she was a politician".

She did, however, achieve the presidency of the student Conservative association - "more by diligence", says Campbell, "than by any outstanding political gifts". Sheila Browne describes her as "a very unmemorable person", who seemed to take no pleasure in the opportunities of Oxford life. She was never admitted to the social circle of the head of her own Somerville College. Dame Janet Vaughan's verdict was dismissive: "She had nothing to contribute, you see."

This "snobbish condescension", Campbell observes, was perhaps her first encounter with the liberal establishment - and probably helped to forge "her lifelong view of herself as an outsider". John Major's autobiography offers a strikingly similar picture of his own treatment by what he calls "the sneering classes". Could it be that both were driven upwards by this same sense of exclusion in their early years?

Margaret Roberts's emergence in 1948, as the 23-year-old candidate for the Labour stronghold of Dartford, sprang from a chance introduction at her first party conference to the constituency chairman. Shining her way through the selection process, she was chosen over 26 male competitors. From then, dedication to her political career was to dominate her life. Her brief stints as a chemist, a barrister, and Denis Thatcher's bride and producer of twins, prompt Campbell to analyse the impact of femininity on Margaret's progress and personality.

Her "most explicitly feminist clarion call" - with two election campaigns and marriage under her belt - came in 1952. She then deplored the convention that expected women to give up careers to have children. "The idea that the family suffers is, I believe, quite mistaken... Why not" she asks, "a woman Chancellor - or a woman Foreign Secretary?" History, says Campbell, will not blame her for having followed her calling at the expense of her family. But he does point up the inconsistency between her own practice and the "family first" line she began to preach once her own had grown up.

Daughter Carol - a perceptive witness throughout - has no doubt, when she looks back, that "my mother's political ambitions eclipsed our family and social life". Yet there can be no doubting the impact of her mother's sex in other contexts. "For a party wishing to present itself", in 1979, "as the wind of change without being specific," concludes Campbell, "Mrs Thatcher's gender was a godsend".

But was it perhaps the fundamental cause of her much later - and eventually fatal - loss of enthusiasm for the European cause? When Macmillan opened negotiations with the EEC in 1961, she was content to tackle the issue of sovereignty. If France and Germany can "sink their political differences and work for a united Europe," she proclaimed, "so can we". Again, when challenging Edward Heath for the leadership in 1975, she affirmed (in a statement drafted by George Gardiner, then a Euro-enthusiast) that "The commitment to European partnership is one which I fully share".

But did she? For John Campbell, the most important reason for her "lifelong belief in the Atlantic alliance as the first principle of British foreign policy and her equally instinctive contempt for continental Europeans" was the factor which distinguished her from all her political contemporaries. That was her lack of military experience, itself "the most important consequence of her sex".

Even for "a gut politician", as Campbell rightly describes her, decades were to pass before this instinct asserted itself. Meantime - unlike Keith Joseph, for example - she "never pretended to be a thinker" or even, like myself, a "formulator of policy". Campbell has rightly identified her 1968 lecture "What's Wrong with Politics?", as her only general statement of philosophy before she stood for the leadership in 1975. He equally rightly concludes that in this "woolly, largely conventional" text, she said "little that anyone in 1968 thought in the least remarkable".

She was nevertheless "a politician, and an intensely practical and ambitious one". She had, moreover, a unique ability to "simplify complex ideas and mobilise support for them" - with help from a growing troupe of academic and political colleagues who realised her potential. With a powerful sense of caution, she recognised the need to await the right moment before deciding - bold as it was even then, in 1975 - to break cover.

Only when the parliamentary party had plainly decided to challenge Heath's leadership, and when all other plausible challengers had fallen away, did she allow her name to go forward. That was the moment when sex really did become her secret weapon. For Margaret Thatcher had never made any secret of her ambition, which far surpassed that of any of her Conservative contemporaries. "It was only because she was a woman," says Campbell, "that the possibility she might go right to the top was not taken seriously".

And so the page of British history was turned, for the whole of the quarter century to follow. We are indeed fortunate that John Campbell is around to chronicle it so well

Lord Howe of Aberavon was Chancellor of the Exchequer (1979-83), Foreign Secretary (1983-89) and Deputy Prime Minister (1989-90)