On a recent night in London, Berkeley Square was buzzing. In one corner, customers for the restaurant Sexy Fish were navigating a gold velvet rope, eager to pay $8 for miso soup and $145 for Wagyu beef.

On the other side of the square, a replica rainforest climbed the Georgian façade of Annabel’s, the nightclub where Prince Andrew once held his stag night. Instead of royalty, a large stuffed parrot was clinging to a 30-foot-high tree, and a leopard peered out through the undergrowth.

Further up the square, sprawling across a corner where a vast Porsche showroom used to be, is a restaurant called Bacchanalia. All three establishments are owned by one man, Richard Caring, and all three are completely bonkers.

“This,” said my date, settling into a heavily upholstered banquette, “is without a shadow of a doubt the oddest restaurant I’ve ever been to. Would we describe it as an explosion in a bric-a-brac factory? Or what my mother would have called a tart’s boudoir?”

Let’s face facts: this is no place for serious food.

The first thing to note about Bacchanalia is that although it’s technically a restaurant, nobody goes for the food. The food is beside the point. If you can’t tell a flatbread from a flat cap you’re in the right place, because you’re there so that you can say you’ve been. More importantly, you’re there so you can post it on Instagram and prove it.

The second thing to note is that while it’s technically in London, you wouldn’t know. Once inside, you could be anywhere: Dubai, Moscow, Vegas. Presumably it makes the international clientele feel at home, because a straw poll of my London friends and colleagues unearthed no one who had ever been, had any intention of going, or knew anyone who had. “Bacchanalia?” they all said. “That Richard Caring place in Berkeley Square? Why are you going there?”

Caring is a businessman who’s acquired or created some of the most famous restaurants in London, including Scott’s and J. Sheekey, and now this. Booking a table involved 11 minutes on the phone, came with detailed instructions about the dress code, and ended with a table for dinner at 5:45 p.m. At two weeks’ notice, anything later was impossible.

“Would we describe it as an explosion in a bric-a-brac factory? Or what my mother would have called a tart’s boudoir?”

“Are we having dinner?” said my friend brightly, “or afternoon tea?” The dress code is “unleash your natural flair,” which is a worry. We were told to avoid ripped or distressed jeans, workout trainers, flip-flops, sportswear, or anything “overly revealing.” This would help to ensure, the Web site explained, that our time at Bacchanalia would be “as exceptional as possible.” In practice, the dress code for women is corsetry, body-con dresses, stilettos, and Chanel jewelry. Handbags are small, Dior, and sit on the table. The dress code for men is jeans and big watches or, in one case, shorts and a stack of rose-gold Cartier bangles.

No amount of designer bling can compete with the room. The brief to the interior designer could probably be summarized in one word: more. More fabric, tassels, pom-poms, and ribbon; more gold, marble, glitter; more sculptures, and sconces, and stuff. The bathroom doors are carved like cameos, the lintels are marble, and the walls are mosaic. The basins have flower-shaped taps and are made from apricot stone, which it seems fair to assume is marble because everything else is.

The dress code is “unleash your natural flair.”

The restaurant’s theme is Greek-Italian, and the floor is mosaic, like a Roman villa’s. The tables are mirrored, the better to admire the painted ceiling. Gods and cherubs look down on the hoi polloi, and four enormous white sculptures by Damien Hirst hover above our heads. One is a bare-breasted Medusa styled like the figurehead on the prow of a ship. Another is a unicorn.

One wall is a mural of Romans having an orgy in front of the Golden Gate Bridge. Another is covered with a glittering gold bar stocking 16 types of Cognac, from $17 to $610 a glass, and a selection of whiskeys so vast it covers eight pages on the drinks list. The ambient music at 5:45 p.m. featured accordions, except in the ladies’ bathroom, where it was plain chant. Later, it graduated to a sort of Pacha Ibiza vibe for a clientele who looked like they’ve just stumbled out of Le Club 55 in St. Tropez.

Maybe they have. Nothing makes sense. The theme extends to marble busts and sculptures of mythical gods and dead Romans. “And that,” said our waiter, pointing proudly to a Victorian-looking bust of multicolored marble, “is 2,000 years old. It’s the emperor Pompilio.”

The ambient music at 5:45 p.m. featured accordions, except in the ladies’ bathroom, where it was plain chant.

Staff are young, earnest, and in Roman fancy dress. They’re trained to explain the “concept” by reading out the menu. “Here is our list of caviar,” says the waiter, taking my menu and pointing to an area marked “caviar,” “here are the starters,” pointing to the starters, “and here are the main courses. Over here is pasta and sharing feasts, and at the bottom here,” he finished, pointing helpfully to the bottom of the menu where it says “sides,” “are the sides.” These include an assortment of breads for $12.

The food is better than it needs to be, but worse than you could wish. As a rule of thumb, raw is better than cooked. Tuna tartare ($32) was heavy on the citrus, but yellowtail crudo with green-pepper gazpacho ($34) was delicious, as was a Greek salad ($25). Spicy ’nduja-beef tartare was decent ($33), ditto octopus mezze with cucumber and wild-oregano vinaigrette ($28). The fried squid was fine, even if the black-garlic aioli looked like mortar and tasted of nothing, but the wild greens were disgusting ($10) and the “tempura” batter on the courgette flowers was no such thing, more chip shop than izakaya ($30).

Butterflied sea bream with courgette ribbons was measly for $48, and porcini tortellini with fresh peas were horrid: thick, hard pasta reeking of dried mushroom ($36). Roman flatbread was a pizza by any other name, and not a very good one ($22). We passed on the chance to try the popular “Bacchus feasting” options for the whole table, which included truffled lobster pasta and 40-day dry-aged rib eye.

Do you have chips? I asked. “No,” said the helpful waiter, “but we have steamed baby potatoes with red onion, capers, and preserved lemon.” It’s surreal.

The clientele didn’t care. They were mostly young, mainly female, and entirely preoccupied with content for their social-media feeds. Two women filmed themselves walking in and spent the first 20 minutes of their strictly timed two-hour slot editing the footage. A table of four in their early 20s photographed each other sipping espresso martinis and eyed the food warily, as if it might bite. One of them poked it occasionally with bespoke cutlery stamped with a B, then carefully adjusted her bustier.

At lunch one day, a young woman in a Louis Vuitton T-shirt nursed a margarita, while at the next table a family ate truffled lobster, the toddler in a high chair placated with pasta and an iPad. At dinner, an older woman sipped whiskey in the bar wearing a ball gown, entirely unremarked, while in the basement loos, a gaggle of jolly Mancunians held intensive discussions about camera angles and light.

Its location, in Berkeley Square, is home to some of London’s most striking restaurants.

Was it enjoyable? Yes, but more as a spectacle than as a place to eat. If I wanted to dine at a Richard Caring restaurant near Berkeley Square—admittedly an unusual starting point for a night out—then I’d go to Scott’s, and I do, often.

Bacchanalia glitters and throbs with bored people speaking different languages into identical phones. Even when it’s full, it’s devoid of atmosphere, just tables of random people eating random food in a random place. It’s living proof that good restaurants are much more than the sum of their parts.

“It’s like eating in an airport,” said my date. “I wouldn’t be surprised if half the punters have hand baggage and an inflatable pillow.” He’s worked his way through a few wine lists around the world and come up with “the Tig Index,” an insight into how much a restaurant marks up its wine.

He jokes that you can tell with reasonable accuracy where you are by how much they charge for Tignanello, the high-end Italian red. If it’s less than $250, you’re in Italy or you bought it yourself; $350, you’re in the U.K.; $500, you’re in Gstaad; $600, you’re in a beach club in Ibiza or St. Tropez; and $700 a bottle or more, you’re in Dubai. Or, as it turns out, Bacchanalia.

Not long after eight o’clock at night, we emerged blinking into the light and looked around. “Goodness,” I said, “we’re in London. Who knew?” A Warhol silkscreen of the late Queen gazed impassively at us from the auction house across the street. In a square clogged with supercars, where Clive of India once held court, huge tents were going up for a luxury art fair, and the parrot at Annabel’s was limbering up for a busy night. They say nightingales once sang in Berkeley Square. If they ever did, they’re long gone.

Hilary Rose is a longtime columnist and features writer at The Times of London