For the past three decades, many Britons had hoped the rigid class system that defined their country from Dickens to “Downton Abbey” was finally dying. Now they fear that class, their old bugbear, is back on the rise.

From 1979, Britain was led for more than a decade by Margaret Thatcher, a grocer’s daughter, and then by John Major, the son of a music-hall entertainer. The current leader, David Cameron, is a descendent of King William IV whose Cabinet is stacked with men, like him, from the country’s toniest private schools and Oxford and Cambridge universities.

Even entertainment has a more upper-crust flavor these days. A recent Sunday Telegraph story with the headline “young, gifted and posh” said Britain’s oldest private schools, such as all-male Eton and Harrow, had become a “production line of young talent,” including “Homeland” star Damian Lewis and Benedict Cumberbatch of “Sherlock.”

Major, alarmed by the apparent reversals, recently sparked a flurry of debate with a speech that made front-page headlines.

“In every single sphere of British influence, the upper echelons of power in 2013 are held overwhelmingly by the privately educated or the affluent middle class,” Major said. “To me, from my background, I find that truly shocking.”

So is it true that class divisions are deepening again?

While the ancestral upper caste still retains its mystique in Britain, the numbers reflect a more complicated reality. An elite still dominates, but it is now a club where money — and the education money can buy — counts more than lineage.

This means more women, ethnic minorities and foreigners have made it to the top. But the increase in diversity masks the fact that it’s becoming harder for the poor and unconnected to climb the social ladder, as the government’s social mobility commission concluded in a hefty report published in October.

A new wealthy class

When the Sunday Times newspaper published its first annual “Rich List” in 1989, Britain’s wealthiest individual was Queen Elizabeth II. The top 10 was dominated by established British property and business owners, including the Duke of Westminster, who owns vast swaths of central London.

The 2013 list is a roll-call of international capitalists who have made London their base, with the Duke of Westminster the only carryover from the original roster. Even the queen has dropped out.

The top 10 now includes Uzbek mining magnate Alisher Usmanov and Indian industrialists Srichand and Gopichand Hinduja.

The changes in the super-wealthy class were triggered, in part, by Thatcher, who deregulated business and banking and opened up London’s financial sector to the world.

Philip Beresford, who assembles the list, told the BBC that “when I first started 25 years ago about two-thirds of the rich list were people who had inherited their wealth. Today, approaching 80 percent are self-made and that’s really a legacy of the Thatcher years.”

The song and dance

If the bastions of business, politics and the professions were hard for working-class people to storm, there was always entertainment, where a working-class hero, as John Lennon put it, was something to be. You don’t need money or a degree to be a movie star or play rock ’n’ roll.

Or do you?

Britain’s leading actors appear to be drawn from a smaller pool compared to a generation or two ago.

In a list of actors with the highest cumulative box-office earnings on website Box Office Mojo, there are 10 Britons in the top 50. The older end of the list includes actors from working-class backgrounds such as Michael Caine, son of a fish-market porter, and 55-year-old Gary Oldman, son of a sailor and a London housewife.

As the list gets younger, it climbs the social scale: Ralph Fiennes, 51, grandson of a wealthy industrialist; Helena Bonham Carter, 47, whose great-grandfather was a British prime minister; and Orlando Bloom, 37, educated at private school.

“I look at almost all the up-and-coming names and they’re from the posh schools,” actress Julie Walters said recently. “Don’t get me wrong … they’re wonderful. It’s just a shame those working-class kids aren’t coming through. When I started, 30 years ago, it was the complete opposite.”

If actors are becoming posher, surely there’s still plenty of room for working class heroes in popular music?

There’s a growing perception — though hard proof is elusive — that the upper classes are gaining ground in the music business. For every working-class singer made good, such as Adele, there’s a posh, privately educated Coldplay or Mumford & Sons. These days in Britain, with the rise of talent-show acts and performing-arts training academies, the grassroots approach is no longer the main way to fame.

That leaves sports — especially soccer — as the one arena whose stars are overwhelmingly working class.

Back to school

In most areas of British life, success comes down to going to the right — usually expensive — school.

A third of Britain’s lawmakers, half its senior doctors and more than two-thirds of its High Court judges went to private schools, which educate just 7 percent of British children, according to statistics compiled by the British Parliament.

Advocates of greater social mobility point to the education system as the key to loosening the grip of a wealthy elite. Some lament the demise of Britain’s academically rigorous grammar schools, where pupils were selected by exam at age 11.

But the grammar schools were largely abolished in the 1970s because the system put most children on a lower-tier track that gave them little chance of attending university. Now middle-class parents with means move to areas with the best state schools, or send their kids to private schools, building what critics say is an educational fortress that starts at kindergarten. In the end, British society faces a fundamental problem: For talented poor people to succeed, some less talented rich people will have to fail.

“If you talk about having a more meritocratic society … we would have to have much more downward mobility than we do,” said sociologist John Goldthorpe.

And there’s the rub.

Downward mobility: Who’s going to campaign on that?