Jumeirah Carlton Tower Hotel, Cadogan Place, London SW1 (020 7858 7250). Meal for two, including drinks and service, £220

At the Rib Room you are never alone. It doesn't matter whether you might wish to be; whether you thought you might have a quiet, relatively uninterrupted chat over dinner with your companion. The waiters will still come at you in waves, fiddling with glassware, fidgeting with bread, asking you how everything is.

"Not sure, mate," I wanted to shout. "Every time I'm about to taste something you come up and ask how everything is." Not that they are completely unhelpful. Having asked to be moved from an over-lit table in the middle of the room to a corner banquette, we were handed one of those flashlights on a flexible stem for reading books by. "We find this is a rather dark corner," the waiter said, "so we thought this might help." He wasn't wrong. This is the first time I have found myself in a space so dark that I literally needed a torch to read the menu.

It read well. Sadly, reading well was pretty much all it did, which was a disappointment. Eating at the Rib Room at the Carlton Tower Hotel is a Knightsbridge tradition, much like money-laundering and Botox. When the hotel opened exactly 50 years ago it was the tallest in London and the oak bar with granite inlay in the restaurant was the place to be seen. It has a reputation for being a little bit flash and a little bit louche but for trading in the most basic of virtues: prawn cocktails, ribs of Aberdeen Angus beef and so on.

Back in 1961 it described itself as offering: "A gourmet's feast in an atmosphere of masculine hearty good cheer," which makes it sound like a rugby club changing room, complete with the smell of Ralgex.

I'm not sure much has changed. Today it's the kind of place where older gentlemen like to take their nieces and chaps with broad necks and suits that shimmer under the down lighters talk softly of the old days in Odessa before they all struck it rich.

And rich they must be for, famously, the prices are brutal. Recently the Rib Room went through a makeover, to give it a new interior in shades of green and amber, and a new chef with experience at Northcote Manor in Lancashire. The website now talks about his commitment to local produce which is all very now and all very silly in this corner of London, unless they really are digging up carrots from Battersea Park. Or shooting the ducks on the scum-laden boating ponds. Which they aren't. In any case it probably is best to get the scallops from Orkney rather than, say, the Thames down from Bermondsey.

The scallops, a plural apparently achieved by the slicing of one large one into three, came nicely seared, and laid on what was described as apple-glazed bacon, but was instead something half an inch thick and soft and braised and an insult both to the word bacon and to the pig. At £16 we expected more. A lot more. By comparison the thickly piled Rib Room prawn cocktail for the same price almost felt like good value (though only if you did happen to get lucky in the botched nationalisation of Russian public utilities all those years ago).

The famed Rib of Beef, an inch-thick hunk of Aberdeen Angus served with gravy and a Yorkshire pudding, is listed online as costing £40. Get to the Rib Room itself and suddenly it's £42. Why is it never the other way round? There are lots of jokes I could make here about how, for that price, you'd want the animal to come out and give you a dance and a xjoke, perhaps a tour of the new dining room. But, actually, I'd have happily settled for it tasting nice. In the 60s the Rib Room declared their ambition to serve the best beef in London. Today I'm not even sure it's the best beef on Cadogan Place.

The meat was completely under-seasoned and was so much dull, wet cotton wool. I left at least 15 quid's worth of it on the side of my plate, because I simply couldn't be fagged to carry on dragging it through my teeth. The gravy was like an episode of Downton Abbey: it looked all right, but had absolutely no depth. The Yorkshire had the texture of something that had been loitering in the kitchen for a while.

Generally I have little time for people who say they could have made a restaurant dish at home; eating out is about so much more than whether you can be fagged to cook or not. But I really can make this so much better at home – and at a quarter of the price. Or make that a fifth of the price, for side dishes – a thin cauliflower cheese, a more pleasing bowl of spinach with shallots – are £4.50 each, or just over a fiver if you chuck in the obligatory 12.5% service. Funnily enough online they are listed at £4. Sorry to bang on about this but, given they have literally just re-launched, the under-pricing online feels like a conveniently sloppy mistake.

A more complex duck dish – a bit of breast, a braised and re-formed leg, some figs – was exactly the same. It was a big plate of blah, an essay on the finer points of dull and, in the darkness of our corner, didn't even have looks going for it. "If they'd put as much effort into the food as they do at hounding us with waiters it might have been a good meal," said my companion. She had a point.

The best part of our dinner was a light, wobbly apple-crumble soufflé, which lived up to its title. Far less appealing was a martini glass layered with an (over-) set cream of white chocolate and cardamom, and a coffee and whisky jelly, all of it beneath a thick layer of milk foam. The latter was the stuff of so many adolescent school-boy jokes that aren't even worth making.

The 500-strong wine list is priced to keep the hoi polloi out and succeeds. There is, it should be said, a cheaper lunchtime menu at £25 for three courses, but for that you get not rib but braised heel of beef, a cut so lowly even the shin looks down upon it.

I am minded to say that after a few weeks of eating outside the capital this is the sort of thing which gives London dining a very bad name and that they wouldn't get away with it outside the M25. But, actually, I don't think they'd get away with it outside SW1. They charge like this for such lacklustre food because they know their clientele don't really care about either cost or quality. And it really shows.

Throughout the meal the waiters insisted on addressing me rather ostentatiously by the pseudonym I had used when booking. "Yes Mr – ", "No Mr – ", "Here's your dessert Mr – ". They did it so much and with such conviction that I began to wonder whether, refreshingly, I actually hadn't been rumbled. No chance. I was in a cab on my way home and looking at my Twitter feed – a filthy habit, I know – when I noticed a tweet from the Rib Room thanking me for dining with them that evening. Amazing. I was a mile away from the place, and I still couldn't get rid of the bloody waiters.

Email Jay at jay.rayner@observer.co.uk or visit theguardian.com/profile/jayrayner for all his reviews in one place