Martin Williams takes his steak seriously – very seriously. The CEO and founder of the M Restaurants empire has based his whole career around knowing his ribeye from his rump. As the former managing director of Gaucho, it pained him to see the steak chain he helped to build subsequently fall into administration over the four years after his departure. So much so, he’s gone back to fix it. And if anyone can, Williams can.

When it comes to providing quality steak, he is fastidious. I’m not just talking about the sourcing here – although, it’s worth pointing out M was the first restaurant in Europe to source 9++ Blackmore Wagyu from Australia and 10++ Kobe beef – but also the preparation.

Earlier this spring, he installed an authentic Himalayan salt chamber (the first of its kind in London) into the M Threadneedle mothership.

Built from hand-picked salt bricks, the chamber helps concentrate the flavour of the meat: the low humidity inhibits the growth of bacteria spores, and the salt particles in the air impregnate the meat. The result is a tenderness and depth of flavour that’s hard to match.

There’s a choice of USDA prime ribeye on the bone, Botswana ribeye off the bone and Galician 50-day aged beef. There’s also charcuterie from venison salami to wagyu biltong. It’s making me salivate just recalling it.

At M, steak might get you through the door, but there’s a lot more to keep you there

Then there’s the sauces: maytag blue cheese; chimichurri; firecracker; black garlic aioli; beef dripping jus. And then there’s the toppings: fried duck egg; malbec onions; black pudding; foie gras. Hell, you can even have half a lobster chucked on top.

But to dismiss M Threadneedle as just a steak restaurant would be a gross injustice. The butterfish sashimi starter was one of the most beautifully balanced sushi dishes I’ve had in London. Living up to its name, the butterfish itself was rich and silky, and was complemented with the tart-tang of ponzu dressing, wispy crème fraîche with a hint of truffle, and topped with dehydrated roe.

On the other side of the steak main, the desserts are reassuringly comforting and calorific. When it’s time to retire for a drink, there are a couple of options. Either go upstairs to the cocktail bar, flanked by enomatic wine machines. Or, if you’re a member, head behind the unmarked door into M Den. The night we were there, the Den had been taken over by Veuve Clicquot and they’d installed a beach volleyball court. But usually, table football is the order of the day (or, rather, night).

At M, steak might get you through the door, but there’s a lot more to keep you there. 

For more information, see mrestaurants.co.uk