There’s a new kid on the block, that block being the same one that the 5 Hertford Street occupies, because the elusive members’ club recently got a new neighbour. 24 Mayfair is London’s hottest new members’ club, a twenty-four hour Gatsby-esque haunt that also houses the Colony Club, a high-end casino.

Strolling along Hertford Street, you’ll know it from the impressive supercars that growl to a halt outside, as high-rollers offload keys to the valet en route to the poker tables. Feeling curious, I recently dressed to the nines and snuck in to take a clandestine peek behind the double doors.

I swiftly wound my way past the reception and into a low lit bar, bee-lining for a corner table. Wiggling onto the royal blue banquette, so plumply padded and quilted that I was in danger of sinking into it, I watched as an impossibly chiselled bartender spun cocktail shakers high into the air. Visitors should be forgiven for thinking they’ve stumbled into the lobby of a glitzy Hollywood hotel circa 1939. Everything from the Art Deco chandeliers to the tasselled cushions and Picasso-esque faces carved into the ice cubes heralded glamour.

It was quickly apparent that 24 Mayfair is different. It’s not your typical members’ club – more suave and lounge-like than the cacophonous mazes of Groucho or Annabel’s. The most obvious difference is sister venue Colony Club, the casino housed under the same roof. And this means that 24 Mayfair’s clientele is different too – this is less ‘see and be seen’ and more a discreet haven where the Mayfair’s elite can kick back and celebrate (or commiserate) after a game.

Upstairs, 24 has pimped up the venue to rival its glossy neighbours. The restaurant mirrors Old Hollywood, with a live jazz singer and guitarist, kitted out in the same blue and gold theme as the downstairs bar, and seats a well-heeled clientele. Being a 24 hour venue, it was unsurprisingly quieter than some other Mayfair establishments when I arrived for dinner at 8.30. I swept through the restaurant to 24’s real gem – the glass encased teppanyaki box overlooking the diners.

Visitors should be forgiven for thinking they've stumbled into the lobby of a glitzy Hollywood hotel circa 1939

This station is devoted to Japanese dining, and the menu is thoughtfully varied. Sushi features heavily – marinated salmon and tuna sashimi are cut beautifully, served with eye-wateringly fresh wasabi and pickled ginger. I chose California crab rolls from the menu, thick with fresh Dorset crab and laden with masago. They don’t scrimp on quality, or quantity. A heap of cracklingly crisp shrimp tempura, loaded with a soy dressing, is main-coursed size. Each shrimp is longer than my hand – I imagine this must be how it is in some of the swankier Vegas casinos. They don’t last very long before they’re snaffled up.

But the big story here is the teppan station, a metal grill over which the chef spins knives and sears lacquered cuts of beef. You can rent the teppan bar out – it seats up to eight – and I’m quite tempted to head back with a group of whoever it is I’m trying to impress. The prices may be high, but the teppan plates are generous and designed for sharing. I decided to go all out, and ordered the ‘24 Teppan Special’ a Japanese smörgåsbord of black cod, tiger prawns and Scottish sirloin. It is prepared in front of me, drizzled in delicious butters and sauces, and served piled onto one plate and steaming hot. It is a seriously good introduction to teppanyaki – I might have to order a few more, just so that I can call myself an expert.

Determined to claw back a semblance of healthy cholesterol levels, I opted for a veggie dish. Happily, it didn’t feel like a compromise: plump and silky enoki mushrooms were heaped onto the grill alongside vegetable rice, deftly spiced and seasoned and tossed into the air on metal spatulas. Had the food not been excellent (which it was) it would have been worth the money for the theatre – this is chef’s table meets private dining, Mayfair-style.

24 Mayfair is offering a lifestyle. The drinks, the dining and the gambling all feel like an upgrade from Hertford Street’s usual fare – 24 Mayfair is more of an ‘experience’, where dinner and entertainment are rolled into one. Quite whose lifestyle it’s aiming to upgrade , it probably isn’t yours or mine (unless you’re nursing some seriously deep pockets), but that doesn’t mean it isn’t well worth a slot in the membership card holder and a firm place on the special occasions rota.

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