Bentley’s Oyster Bar & Grill is on Swallow Street, an alley between Piccadilly and Regent Street, which swallowed most of Swallow Street in the early 19th century. But that did not give it the name. Property developers only memorialise their crimes accidentally and Swallow Street is named for Thomas Swallow, about whom I know nothing else. He does not appear in Ed Glinert’s The London Compendium.

Bentley’s is both inside and outside a squat, ugly and very interesting yellow brick house. It preens like an ugly clever man. It has fine large windows with angry brick eyebrows. Outside, diners sit under square black umbrellas and behind a partition, with glass, in a parody of a private members’ club, but in the middle of a street. There is topiary, heating, an ornamental bicycle and even a carpet. The signage is electric, and bright green, as if written by a copywriter who is also a witch.

It is quite formal for outside dining but Bentley’s is old (it is 102) and very grand. It makes me ponder what Oslo Court would look like if it was partially outside. A rose garden full of chickens probably. The absence of cars ensures they do not choke to death on exhaust fumes, but it still feels mad — a private members’ club near a bus lane made for shoppers when George V was on the throne, and who are now dead. The catch of the day is on a blackboard, but this is the smooth and monetised heart of the West End of London, and the harbour at Newlyn feels far away.

Inside, there is a long room with a bar and red booths. It is pared down: there is nothing gaudy here in this restaurant that used to look like the Royal Opera House but no longer does. Someone jumped in and made it generically tasteful; but I have a weakness for themed restaurants and have to be prevented from dining at the Rainforest Café in a giraffe-style hat and then writing about it in The Spectator. A luckless pianist plays behind a curtain opposite the cloakroom. This is weird, even for London W1: why would you employ a pianist you did not want to see, unless it is a sort of Elephant Man pianist in a pillowcase with eye holes, or the actual Phantom of the Opera, in debt and playing in restaurants? In fact, he looks normal, if slightly aggrieved, and I hope he is promoted to the status of having a face fit to be seen by people eating shellfish. I do not know why they do not put him in the street near the bicycle. My companion frets about him, but she has been known to suggest to tramps that they take a course at the Open University.

Because Bentley’s is grand, there are many very literal private rooms (one is called the Crustacea Room, another the Rib Room) but we eat in the dining room upstairs. It is a sombre grey with a polished wood floor, and it is hushed, serious and slightly forbidding. It is not louche, like J. Sheekey, but that is off the Charing Cross Road; and it is not flouncing like Rules. It is for the seafood-eating austere and they are as much fun as they sound.

Here, then, in this poised dining room we eat excellent food from Richard Corrigan’s kitchens: smoked salmon with sour cream and potato blinis, grilled sea bass and Elwy Valley lamb. The fish is better than the meat, of course, and very proper, but Bentley’s is too calm to be joyful, and too self-important to be imaginative. It is a restaurant for people who don’t wish to be surprised. They should release the pianist.