Top tables: restaurateur Jeremy King at the Wolseley

Corbin and King's posh-casual restaurants are hugely popular, a magnet for celebrities – and apparently recession-proof.

Not since the convergence of Auguste Escoffier and Cesar Ritz in the 1900s has there been an impresario partnership like that of Chris Corbin and Jeremy King. In the world of posh metropolitan catering, there's nobody to touch them. They've been called "the Rogers and Hammerstein of relaxed eating".

Their restaurants may not win Michelin stars, but they compensate by being wildly popular with London's intelligentsia. They aren't cheap, but Corbin and King like to insist that money isn't everything. "I always believe," King, has been heard to say "that you give people the opportunity to spend without making it mandatory. Because a lot of the most interesting people who come into restaurants are the least affluent."

Since they met in the late 1970s – Corbin was manager of Langan's Brasserie; King maître d' at Joe Allen's – and joined forces to buy Le Caprice in 1981, they've become the most confident and assured of London restaurateurs. They turned Le Caprice (est. 1947) into an haut-celebrity hangout, where Melvyn Bragg and Jeffrey Archer fought for the all-important Middle Table and where Harold Pinter endured interviews with starstruck journalists (such as moi) at three-bottles-of-Chablis lunches.

In 1990, after six years of trying, Corbin and King bought the run-down theatreland dive, The Ivy (est. 1917) and turned it into the most in-demand eaterie in the West End. It was easier to get into the vaults of the Bank of England than the Ivy if the maître d' didn't know or like you. Models, film people, rockers (such as Ronnie Wood, who painted a striking group portrait of the regulars) and publishers hung out with MPs and TV stars. Sir John Mortimer, the author and champagne socialist, was always in, starting lunch with bubbly and moving on to bangers and mash. The screenwriter Alan Scott (who wrote Don't Look Now) booked a table every day for years. The Hardens guide voted the Ivy "Favourite London Restaurant" for nine straight years.

In 1997 they bought J Sheekey (est 1896) the venerable fish restaurant. A year later, having performed miracles of renovating three moribund eating houses and making them shriek with trendiness, they sold their company Caprice Holdings.

Their new operation, CKL Restaurants, opened The Wolseley in 2003. It was originally built in 1923 as a Wolseley car showroom with marble pillars and Venetian arches, then spent 70 years as a bank and was renovated in palatial splendour. Corbin and King said they wanted to conjure the spirit of the grand cafes of 19th-century Europe: Paris, Vienna, Berlin, Budapest.

It was an instant hit, boasting the highest grossing turnover of any UK restaurant. And it drew an eclectic clientele that included City grandees and Lucian Freud.

The succession of Corbin/King acquisitions speeded up. The Delaunay, a gorgeous Art Deco sister to the Wolseley, opened last December, followed by the massive, 220-covers Brasserie Zedel in August and, last week, Colbert on the site of the ill-fated Oriel in Sloane Square, Chelsea, beside the Royal Court Theatre.

Three new restaurants in 10 months? Aren't they over-reaching themselves? Jeremy King smiles his sleek, greeter's smile: "I'm overwhelmed," he says. "There's been more interest in Colbert than in anything we've ever done. There weren't too many good words about the Oriel, but everyone seemed to miss it. This site had an important role in the community and we're aware of our responsibility to it. That's why we're trying to make it seem like it's been here since before the war."

The Cadogan family, which owns the site, reportedly decided to sell in 2008 after the Earl of Cadogan had a "disappointing" (and overpriced) lunch there. Apparently, 75 people made serious applications to take it on. How did Corbin and King win it? Someone who saw the competition specification told me: "You could easily imagine that the landlord was describing the Wolseley."

Initially, the duo planned to design the place as another Wolseley. But they gradually realised that locals yearned for a typical Parisian boulevard cafe – as Oriel was meant to be. How did they brief the designers (the David Collins partnership) about Colbert's style? Unexpectedly, Jeremy King gives you a detailed life story: not his own, but of an imaginary person who embodies the new establishment.

"I think of a Frenchman on the run from Paris, let's call him Pierre, because he seduced the owner's daughter at the Café de Flore.

"He came to London in the late 1920s, when Chelsea was a subdued area, and had just enough to open the bar here." (A brasseur is French for brewer, so a brasserie is where the brewer sells beer and serves food with it.)

"He opened a pub, and people took it to their hearts and he was able to acquire the shop next door, and eventually another, and here we are."

King caresses the details: how the cornicing varies from room to room, how the floors, the panelling, the colour of the leather banquettes differs from space to space. The photos and posters in the dining-room are of pre-war Paris, the city during the Liberation and Paris in the monochrome 1950s. He plans to have contemporary movie and music posters on the walls. He and Corbin have a passion for set-dressing. The restaurant critic Jay Rayner shrewdly noted that they turn restaurants into film or theatre sets, where "they have created poised British costume dramas, flogging tickets to those who can afford their brand of Mitteleuropean (by way of belle époque Paris) good taste".

Since the same dishes tend to crop up on the menus at sister restaurants – Wiener schnitzel, choucroute de l'Alsacienne, moules, strudels, tartes, coupes – is there a danger that they'll be taken for a chain, rather than a family?

"We never want to be taken for a chain," said King, firmly. "You must remember that people living in Paris before the war could tell what the menu at a new brasserie would be like without actually going there. There are some long-established, standard dishes. And though there's some crossover between Colbert and Zedel because they're more French, there's very few dishes that turn up everywhere."

One thing that does turn up everywhere is Mr King. Diners at the Wolseley and the Delaunay are used to seeing the 6ft 4in co-proprietor, built like a Guards officer and resplendent in a double-breasted grey suit, looming over them with an encouraging smile. King was the first "greeter" I ever encountered, at the Ivy in 1988; did he invent the concept? "No, though we might have heightened people's awareness of it. Proprietorship has been around for a long time. What sets us apart is that we're intent on being restaurateurs rather than restaurant owners. The best restaurants aren't the ones with the snotty maître d'. The best restaurants are proprietor-led."

What did he make of the Michelin star system? "I don't understand it. Like many things in life, if you lose sight of what you're doing, you start to use desperate measures. So Michelin dropped its insistence that restaurants had to have three types of breads and soignee loos and tried to be more groovy, but that just confused people. There's no reason why the Delaunay shouldn't have a Michelin star since the food there is as good as the food at many a Michelin-star place; it's just we don't fancy it up."

Contemplating Corbin and King's small empire of trendy eateries, you can only guess at the number of possible sites and renovations they've considered over the years. King reckons that for every restaurant they open, they've looked at a hundred potential ones. They've considered starting a Wolseley clone in the Shanghai Bund and helping Graydon Carter of Vanity Fair renovate the Monkey Bar in New York's Elysee Hotel. Soon, they'll be dipping a toe into boutique hoteliership with the 73-room Beaumont Hotel, near Berkeley Square; but that won't open until 2014. At present, says King: "At present, we haven't got our eye on anything at all." Frankly, it's hard to believe him. Dame Rumour informs me that the duo have designs on Langan's Brasserie in Piccadilly, where Corbin worked in the 1970s.

It's impossible to imagine such a buccaneering pair passing up the chance to seize such a treasure on London's culinary bounding main.