LONDON, NOV. 27 -- To his critics, Britain's next prime minister is a dry, gray, diffident man who acts, looks and talks like the bank clerk he once was -- "the blankest sheet of paper around the cabinet table," the Guardian newspaper once complained.

But John Major embodies Margaret Thatcher's vision of an upwardly mobile, meritocratic society in which the best and brightest can rise to the top unfettered by class or social origins. And his breathtakingly rapid accession to Britain's highest office is in many ways the ultimate vindication of her philosophy.

Major's success at first glance seems more a version of the American dream than a British one -- except that no American president in modern times can claim a background as humble as his. And few could claim his sense of normality: He sends his two children to state schools, he has a wife who refuses to move to London, and he shocks some of his more elegant civil servants by dining alone on baked beans on toast at a cafe on many working nights.

His father, who was 66 and nearly blind when Major was born in 1943, had tried and failed at many strange and colorful jobs, including trapeze artist, vaudeville performer and minor-league baseball player in the United States. Much of Major's childhood was spent in a two-bedroom tenement apartment in Brixton, one of south London's poorer but more respectable working-class neighborhoods. The family shared a hallway bathroom with other tenants, and one of the neighbors was a cat burglar.

Major says he hated high school, and he left at 16 to help support his family but struggled to find work. He drew unemployment benefits of less than 3 pounds per week for eight months and failed the entrance examination to be a bus conductor. He worked as a clerk and a laborer mixing concrete. He once told an interviewer "you haven't experienced life" unless you've had breakfast at 7:30 a.m. at a cafe after having already put in two hours of hard labor.

At 18, he put his workman's gloves away, passed an entrance exam and joined the Standard Chartered Bank as a junior clerk, rising steadily through 14 years there. He found his way into Conservative Party politics first as local councilman in Lambeth in south London. He lost two campaigns for Parliament, then won a seat in 1979 on Thatcher's coattails when she became prime minister.

Thatcher entered office with a fairly traditional cabinet of Tory elders and many so-called "wets" -- those on the party's left. Gradually and bruisingly she weeded them out, replacing them with younger, more radical and, in her view, more competent managers.

Thatcher's aides say she picked out Major early. He was a young assistant parliamentary whip invited to a lunch with the leader with about a dozen of his colleagues. When Thatcher, as was her style, launched into a long lecture on economic policy, they say Major alone disputed what she was saying and the two engaged in a long, heated argument. His friends went away believing Major's career was finished -- but Thatcher liked what she saw and heard.

She rewarded him in 1985 with the same post she had first held in administration: parliamentary undersecretary of state for social security. A year later she appointed him social security minister. And in 1987, after she won her third straight term in office, she made him chief secretary of the treasury -- the first of the class of '79 to join her cabinet.

Two years later, Thatcher made clear she was grooming Major as a successor. She shocked the party by naming him foreign secretary -- a post for which he had no experience. Three months later, when Nigel Lawson resigned from Thatcher's cabinet in protest, she switched Major to Lawson's post as chancellor of the exchequer.

His friends say Major impressed Thatcher because he was smart, unpatronizing and politically skillful in inflicting sharp cuts on cabinet ministers' budgets without alienating them. Skeptics give another motive: with so young and inexperienced an heir apparent, Thatcher could plan to hold office for many years to come.

As her protege, Major dwelled in Thatcher's shadow and his own political beliefs remain obscure. He was a tightfisted but politically sensitive chancellor who kept interest rates in double digits and oversaw an economic slowdown that produced increased unemployment in a drive to lower inflation. "People must understand that if they have jam today, they may not be able to afford butter tomorrow," he once warned.

It is known he opposes capital punishment and favors more spending on schools. As a lowly member of Parliament, he joined the Blue Chip Group of young lawmakers on the party's left. As social security minister, he devised a draconian plan to restrict payments for extra heat to retired people during the winter of 1987 -- but backed down four days later after strong public protests.

"He is sympathetic to the worst-off in our society," said Timothy Raison, a "wet" Tory who was once Major's boss. "I always felt he was at least a crypto-ally."

Major worked closely with Foreign Secretary Douglas Hurd to cajole Thatcher into allowing Britain to join the European exchange-rate mechanism earlier this fall, and he is expected to be more of a pragmatist on European issues than she was. Many thought he would defer to Hurd in the race to challenge Michael Heseltine after Thatcher stepped down last week, but he jumped in instead, recruiting allies with an aggressive campaign that propelled him to victory.

One of the key themes of his brief campaign was his working-class origins and his understanding of "the common man." While Hurd was forced virtually to apologize for graduating from Eton and Oxford, and Heseltine played down his own Oxford education, Major boasted of his own lack of formal schooling.

Many loved it. "The time has long past when we want the pampered patronizing classes at the helm," editorialized the Star, one of Britain's raunchier tabloids.

Major may sell less well overseas, especially when compared to his famous, combative predecessor. His three months at the Foreign Office were said to be difficult; he reportedly grew angry at the amount of material he was expected to master in a brief time. Thatcher undermined him publicly at a Commonwealth conference in Malaysia last year when she denigrated a compromise on South African sanctions he had painstakingly negotiated.

Major's wife, Norma, 45, is a former home economics teacher and an opera buff who has written a biography of Joan Sutherland. She and their two teenage children live in Huntingdon, some 60 miles north of London, and she only spent one night a week at 11 Downing Street, the chancellor's official residence.

She says she lost 14 pounds in the three months he was foreign secretary and was reduced to tears several times by the demands the job placed on her husband. "I suppose John ought to be the center of my life, but he's not because he's out of it so much of the time," she told an interviewer last year.

The Guardian, one of Major's critics, has conceded that he is "calm and adroit," but complained that "no one, still, quite knows what he stands for." It called him "the canniest candidate, with drive and organization to admire; but he is the biggest gamble."