Recession? What Recession? Pass Me Some Grapes.

The show starts in the foyer.

Guests are greeted there by women in dark red togas wearing gilded arm cuffs, looking like they just walked off the set of “Ben-Hur,” the 1959 Hollywood epic about the Roman empire and chariot races. The women are here to take your coat, then hand you off to a colleague who appears to be dressed as an extra from the same movie, who will whisk you through the door and into the theater.

Strike that. It’s a dining room, albeit one so eager to project theatrical opulence, and so crammed with color and lush fabrics, that it seems to belong on a stage.

This is Bacchanalia, a new restaurant in the ritziest corner of one of London’s richest neighborhoods, and a place as gleefully out of step with the grim temper of this country as a clown car at a wake. You can either recoil at the cartoonish debauchery of it all, or surrender to this immersive production and snap some selfies, along with everyone else.

The latter option is a bit pricier. The lobster paccheri pasta, with black truffle and creamy bisque sauce, costs $162 and a cocktail called Freddo, made of Don Julio Blanco and Don Julio 1942 Tequila, cocoa butter, coffee and banana, is $31. Ready for dessert? The large portion of tiramisù will set you back $42, and its top tile of chocolate will be hand cracked for you by a waiter with a spoon.

Everything about the place feels like a dare. Rubberneckers are dared to tsk-tsk its celebration of high-end gluttony. Rival restaurateurs are dared to imagine a more outrageous concept. (Good luck!) Customers are dared to concentrate on their food, which is a challenge in a room bustling with waiters cosplaying right down to their sandals, and overstuffed with enough art to fill a few rooms in a museum.

This includes five huge and fantastical white sculptures by Damien Hirst, which soar overhead, one of them a flying unicorn carrying two naked lovers, preparing for airborne bliss, as well as a floor-to-ceiling work that reimagines Thomas Couture’s 1847 painting, “The Romans in Their Decadence.” It looks very much like the original except that a few of the louche and classically attired revelers are using laptops and mobile phones. The original was meant by Couture as a rebuke to the Romans, who look bored and exhausted by their orgy and whose empire is doomed.

So the updated image captures the restaurant’s theme: Inspired by the civilization that invented excess, let’s overdo it. Then post it to Instagram.

More than anything, Bacchanalia feels like a dare to everyone in Britain who is not dining at Bacchanalia.

England, Wales, Scotland and Northern Ireland are enduring some well-publicized financial agonies: tax hikes, cuts to public spending, double-digit inflation, rising fuel costs, and what has been described as a “short and shallow recession,” which threatens to become something worse. There have been strikes by ambulance drivers, border control staff members and transportation workers. Brexit has multiplied the supply chain woes that have afflicted countries across the world.

With U.K. deficits already swollen by years of Covid-related payouts, austerity is the only medicine that the Tory government says is left in the cabinet.

“There was a period when austerity is what happened to other people, but now everyone can see their gas and tax bills go up every month and it’s terrifying,” said Oliver Bullough, author of “Butler to the World: How Britain Became the Servant of Tycoons, Tax Dodgers, Kleptocrats and Criminals.” “That restaurants like this are still opening despite the fact that people in the rest of the country are deciding whether to heat or eat is pretty bonkers, really.”

By coincidence, the day that Bacchanalia opened, on Nov. 17, was also the day that Jeremy Hunt, the chancellor of the Exchequer, announced in a speech to Parliament nearly $30 billion of tax increases and $35 billion in spending cuts.

“Anyone who says there are easy answers is not being honest with the British people,” he said.

The party a few hours later at Bacchanalia seemed to occur in an alternative universe. Guests in cocktail dresses and tuxedos mingled with the likes of Emma Thynn, the Marchioness of Bath, the fashion designer Harris Reed and the model Naomi Campbell. Performers in nymph costumes flanked the doorways, moving with the mannered slowness of living statues, while toga-clad waiters wearing laurels replenished flutes and served canapés. A performer dressed as a glittering Cupid prowled the mezzanine, slowly arching his bow at the crowd.

The Nero of this ersatz Rome is Richard Caring, the perpetually tanned, improbably taut and usually grinning Brit who is often described in the national press as a billionaire and who started his career importing cheap clothing from Hong Kong. Around 2005, he segued into the hospitality business and today owns an empire of mid- and high-priced restaurants here, many of them better known for buzz and snazzy décor than quality cuisine.

A few, like Bacchanalia, border Berkeley Square, a verdant patch of Mayfair abutted by luxury car dealerships (Ferrari, Bentley), social clubs and the London outpost of Blackstone, the private equity giant. It is the playground of oligarchs, petrogarchs and hedge funders. They can dine at Sexy Fish, a Caring creation where eating is “like being punched in the face by Dubai” as The Spectator put it. Across the square is Mr. Caring’s most treasured bauble, a private members’ club called Annabel’s with six restaurants and an immense grizzly, made of twigs, standing in the forest-themed men’s room, a visual pun on the old joke about where bears relieve themselves.

Mr. Caring would not comment for this article, nor would the publicity department of his company, Caprice Holdings, explain why he would not comment. This is surprising because he’s typically very chatty with the media and months ago decided to lean into the unbridled hedonism of Bacchanalia. In the run up to its opening, the restaurant announced that it was looking for “London’s first grape feeder,” which was advertised in a full-page ad in The London Times. (Job requirements: “gorgeous hands” and a “basic grasp of Greek and Latin.”) Hundreds applied for the job, and all were disappointed. The posting was a publicity stunt.

In early November, The Evening Standard, a free daily, asked in a roundup of new restaurants if Bacchanalia was “a toga too far in troubled economic times.” Not to Marcella Martinelli, a stylist who was a guest at one of Bacchanalia’s launch dinners.

“Obviously the cost of living crisis is important,” she said. “But if you can afford this, it’s an experience. As long as they get the pasta right — that’s all that matters.”

Alec Gunn, the chief executive of a warehousing company, who was an early Bacchanalia diner, said he felt that such theme parks of overindulgence were important for the London scene, and that they were aspirational. “I’ve worked hard all my life,” he said. “People deserve to have some fun.”

Mr. Caring concurred in remarks that he made on opening night, before and after he mingled with attendees, while being trailed by a large man with an earpiece. He seemed acutely aware of the chasm between the festivities he’d orchestrated and the misery everywhere else.

“The last guy that made a speech in these sorts of surroundings started with ‘friends, Romans and countrymen,’” he began, quoting Mark Antony from Shakespeare’s “Julius Caesar.” (By that point in the play, Caesar has been stabbed to death.)

He wanted a haven for conspicuous consumption, he went on, a place that offers escape for those who can afford it.

“Is it a toga too far?” he asked the crowd.

“No!” the crowd shouted back.

At a time when restaurants are scrabbling for waitstaff, part of a broader labor shortage, Bacchanalia one recent afternoon was crawling with employees. (Higher pay is the secret, one of them explained.) They are an efficient and helpful group, identifiable through an elaborate hierarchy of outfits and brooches that seems to echo the stratification of ancient Rome.

At the bottom are runners — the men and women who deliver the food — who dress in workaday togas, and jobs rise in status from there, segueing to chic western attire for those at or near the top. The assistant bar manager, for instance, wears a sports jacket of burgundy velvet; the bar manager wears the double breasted version of the same garment, which is incrementally fancier.

Like it or not, diners are automatically part of this caste system, updated versions of the sybarites depicted on the many murals. Given the fate of the Roman Empire, the role comes with a tricky edge. Though Mr. Bullough, the author, conceived an idea that might make customers even more uneasy.

“Next year I anticipate someone in Mayfair will open a replica of the first class deck of the Titanic, with prices to match,” he said, “and then we’ll know we’re all doomed.”