Walk down Charing Cross Road, in London's West End, past Leicester Square Tube station, past Wyndhams Theatre where the jukebox musical Dreamboats and Petticoats is packing 'em in, and turn into the little enclave called St Martin's Court. Before you on the right, under eight awnings, is a striking establishment. The frontage is a camp extravagance of dusty magenta. You can't see through the windows because tinted mirrors obscure the view, but there's something decidedly raffish about the place. It's old but still lively, like a panto dame in plum taffeta.
Push through the door and you'll find yourself in a shrine to British theatreland. The walls are festooned with portrait photos of venerable thespians: Olivier, Wolfit, Hepburn, Niven. The decor is old-fashioned, but in a good way. The napery is as white as Scarlett Johansson's teeth, the cutlery shines. French waiters in dinner jackets and bow-ties regard you with a just-about-friendly supercilium.
You have entered, gentle luncher, the hallowed temple of fish cooking that Londoners call Sheekey's. Under its trade name J Sheekey, it's been here, in many incarnations, for 116 years, through wars and Blitzkrieg, Swinging London and Recession London, highs and troughs of fortune, but it survives and flourishes. Its appeal is partly its expertise with fish – the chefs know everything about the lifespan, breeding habits, succulence and texture of the piscine world – and partly the patina the restaurant has taken on with years. It's not London's oldest eating house – that would be Rules in Covent Garden – but it is to fish cookery what that elderly shrine is to game. And its antiquity gives it class, like a small stately home. Once, in the main restaurant, I clocked Anita Brookner lunching with her agent, Bill Hamilton; she smoked all through her main course, holding a cigarette in the same hand as her fork, inhaling after bites, the image of posh-county decadence.
Without waiting for its 120th anniversary, its owners, Caprice Holdings, have commissioned a handsome cookbook, J Sheekey Fish – 320 pages of fishy, crabby, scallopy, lobstery, shellfishy, haddocky loveliness, with words by Allan Jenkins, editor of Observer Food Monthly. We learn from him that the original J Sheekey's was Josef, though no one knows his nationality. He was a fish and oyster trader in Shepherd's Market, Mayfair, who in 1896 was granted a licence by the Marquess of Salisbury, "to serve poached and steamed fish, shellfish and seafood" to the public in St Martin's Lane, provided he also supplied meals to Salisbury's legendary after-dinner parties.
Beyond that, says Jenkins, the history is a little sketchy. "On the day the book was published, I heard from Martin Fielding, the son of Leslie Fielding, who was manager of Sheekey's in its 25-year heyday, from 1947 to 1972. Leslie was the nephew of Josef's daughter Mrs Emmy Williams, a formidable matriarch. We learned from Leslie that in Sheekey's early days, there were no male chefs in the kitchen, only women cooks. One of them used to talk cooingly to the lobsters, just before she lowered them into boiling water. And we learned that Charlie Chaplin was a regular when he visited London once a year."
Over lunch at the newish (2009) J Sheekey Oyster Bar extension, I meet Tim Hughes, executive chef of the Caprice Group. What, I ask him, were the key differences between cooking in 1896 and today? "In those days there was a lot more steaming and poaching," he says. "The British palate used to be blander than it is now. Sheekey's was famous for its boiled fish, mainly because the Earl of Salisbury wouldn't allow frying on the premises. He thought it was too déclassé, and would downgrade the area.
"They used to cook everything for such a long time," Hughes continues. "Scallops came as Coquilles St Jacques, on the shell with a Mornay sauce and mashed potato – cardiac stuff. All the sauces in those days were classic, very heavy. These days it's much lighter and lets the fish taste of the sea."
Oysters used to be the poor man's food in Victorian times, but now sell in Sheekey's at £15 for six. Have the fortunes of other shellfish changed over the century? "Razor clams," says Hughes, "they've come into their own quite recently. Before, they didn't know how to cook them properly. You've got to steam them until they pop open. If you cook them a second longer, they're like rubber. Scallops have always sold, but they used to soak them in water until they'd go spongey. A scallop should never touch water."
Some of the Sheekey menu is posh comfort food – fish pie, fish and chips – but some aims for more ambitious flavours. Such as their monkfish osso bucco with gremolata, and their smoked haddock with colcannon, poached egg and mustard sauce. Mostly, though, their watchword seems to be simplicity. Hughes believes that, when cooking fish, less is all.
"Dover sole costs a huge amount and you can't do anything with it, except season it, cover it with butter and grill it for 10 minutes," he says. "I find that quite pure. Same goes for salt-baked bass – you just cover it in salt and cook it. But sometimes we might add ceps, because their earthiness goes great with the beautiful sweetness of bass. We don't use vegetables with big flavours that don't go with the fish. We do sauce on the side, but keep the natural flavours. We stick to European styles of cooking. We don't have any tuna on the menu, or anything exotic, like swordfish. It's mainly fish from British shores."
The only contemporary touch in Hughes's conversation is his keenness on sustainability and seasonality. As well as tuna, he won't have skate, eel or huss, "because they're on the endangered list". He won't use plaice in autumn "because they're full of roe" but recommends Dover sole, brill and turbot. "And the native oysters are in," he says with pleasure, as though welcoming back long-missed friends.
Familiarity is what Sheekey's is about. Generations of fish- and shellfish-lovers have come to trust that they'll be served the best fish in the land at Sheekey's, and it won't be mucked about with. But it's also well-known as a hang-out for the rich, theatrical and famous. How does it differ from its Caprice Holdings' stable-mate, Scotts of Mayfair?
"The clientele here are Londoners, it's very much a theatre restaurant, but it's not a showy place," says Hughes. "It has lots of little rooms. You can come with your grandma, your kids, anyone and enjoy it and not be on show. Whereas Scotts is Mayfair, it's a bit grander, it's a show-off place."
In my experience, people feel they have a relationship with Sheekey's, a familiarity with the barely changing menu, a feeling, on arrival, that you're about to have a predictably warm and enjoyable couple of hours. You may spot famous faces from the acting and writing worlds, but you never feel they've come to be seen.
"We never get the paps [paparazzi] here," says Hughes, "because it's down a backstreet and – well, its Sheekey's. The paps are usually outside the theatre, looking for the B-list actresses. I remember when Sienna Miller was playing in the theatre around the corner, when she and Jude Law were breaking up. All the paps were outside the stage door, waiting for her to come out looking tearful. Then, walking past them up the alley are Ron Howard and Tom Hanks, who are here to film The Da Vinci Code. Here are two of the most powerful Hollywood celebrities in the world. They walk up and down, come in, have their food, and go. And the paps are completely oblivious. That sums up Sheekey's for me."