The Mercer, Threadneedle Street, London

If ever a restaurant suited its surroundings, The Mercer suits the City of London. For one thing, it's located in the financial district's most famous street, only a broker's lurch from the Old Lady herself. For another, the building used to be a bank, and its noble pillars and high ceilings carry a vestigial whiff of a Temple of Mammon. For a third, the décor is, basically, a business suit. The starkly handsome bar is black, the pillars are black, the leather banquettes are black, the napery is dazzling white. The clientele are all in the City uniform of dark grey or plain black undertaker suits and, when they remove their jackets, dazzling white shirts. Their mothers would be so proud.

I've never been in a restaurant so resplendently monochrome. Or so virulently male. I noticed just one woman in the place, looking very pretty in a pink and pale blue shepherdess ballgown (only kidding – she was, inevitably, in a blacker black suit than her male colleague). It would be too oppressive for words, except that the clever owners have run a brass handrail around the banquette, and, with this simple detail, transformed the place into a New York or Chicago brasserie.

The menu is laid out American-style, with a whole page devoted to power-breakfast options, eggs, home-made juices and posh, high-cholesterol (and high-priced at £16) fry-ups. For lunchers, despite some immigrant families of pasta, the tone is aggressively British, from the potted Yorkshire ham-hock starter through the steak-and-mushroom Mercer Pie drenched in London Porter ale, down to the Little Wallop cheese (co-manufactured by Alex James, of this parish). It's a bit relentlessly flag-wavy – as if City eaters might not trust any food they hadn't been served at Charterhouse and Stowe – but appealing none the less.

My friend Sophie, whose yellow frock was literally the only colour (red wine apart) in the room, ordered venison carpaccio with Armagnac prunes, lemon and Parmesan, and was puzzled to find "it doesn't actually taste of game at all, the cheese is very mild, so the flavour is mostly prunes". I agreed. The thin-sliced venison was indeed pure texture, though meltingly soft and given a nicely ragged edge by some rocket. My "London Particular" pea and ham soup, named after a Dickensian fog, was thick and pleasingly crammed with ham chunks, but was decidedly oversalted. Speaking as one who loves salt, and adds it to every meat I ever come across except ham, this is quite a statement. Perhaps, I told our petite, super-chatty Australian waiter, it's the ham that's caused this slick of salinity. "It might be the peas, of course," he replied, archly.

Main courses were much better – two dishes of real substance, colour and beauty, served at the table with drama and pride. Sophie's seabass with braised lentils resembled a Jackson Pollock in its riotous mosaic of reds, yellows and browns. The fish was lightly crispy on the outside, the result of cautious roasting, and firm and moist on the inside. A creamy Hollandaise sauce melted into the lentil bed with baby tomatoes and ensured that Sophie wouldn't need to eat again for 24 hours. "If anything, there's too much going on here," she said. "It's a mixture of spring and autumn, the lentils so heavy, the fish so light."

My roast monkfish tail with creamy curried Shetland mussels was faultless: a real solid lump of this meatiest of fishes, cut from the thickest end, was faintly dusted with curry powder and perfectly cooked, surrounded by delicious mussels, not too strongly spiced. With some thin broccoli and creamed mash, it sang and danced all down my oesophagus, washed down by a £10 carafe of Saam Mountain Pinotage. A major innovation of The Mercer is their Enomatic machine, which opens and closes wine bottles without letting the wine inside encounter any oxygen. It means they can serve any wine on their impressive list by the glass or carafe. This device, mark my words, will transform all restaurant wine activity in the future, just as the screw-top transformed the way we open bottles.

Technically unable to ingest another mouthful, but required by the job to sample puddings, we shared a hefty slab of Bakewell tart with raspberry cream and syrup: it resembled a triangular section of pavement, grounded in jammy seriousness, topped with sliced almonds, and was blissful.

How in God's name anyone, after such a meal, could return to considering interest rates, mortgages and the plunging rate of sterling against the euro is anyone's guess. The Mercer is a rich, solid and sophisticated addition to City life, well worth a lunchtime investment of nearly £100, provided the chef could curb his love for salt. Then again, "salary" comes from the Latin salarium, meaning "salt-money". Maybe it's considered some kind of financial necessity in the Square Mile...

The Mercer, Threadneedle Street, London EC2 (020-7628 0001)

Food
Ambience
Service

Around £90 for two, with wine

Side orders

BRITS IN THE CITY
By Madeleine Lim

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