194 Piccadilly, London W1J 9EX (020 3005 9666). Meal for two, including wine and service: £175 (if you trip up on the wine list)

Earlier this year Jamie Oliver announced he was closing six branches of his Jamie’s Italian chain because, y’know, BREXIT! This was odd. While the industry was reporting cost issues as a result of the referendum vote, no one else had cited it as a reason for closure. What’s more, while the weak pound has increased imported food costs by up to 20%, the bulk of the most expensive items on the Jamie’s Italian menus – the meat – is proudly declared as British. Still, if he says it was down to Brexit and not just that people didn’t want to eat in branches of an increasingly ersatz high-volume Britalian, with a menu full of annoying dish titles – “crunchy Italian nachos” anyone? As against, say, the soggy Mexican ones – then who we are to argue?

Curiously, Brexit hasn’t got in the way of opening a second multi-million pound, gilded and flounced outpost of his grand meat and smoke extravaganza Barbecoa, on a huge site on London’s Piccadilly. Listen carefully and you can hear the money spurting out the door to the landlords. When the first Barbecoa opened in the City in 2011, it was a collaboration with American barbecue expert Adam Perry Lang. It promised to bring American barbecue to London, but didn’t. That was OK, because we have since had Pitt Cue and others to do the job for us properly.

Perry Lang’s fingerprints are nowhere to be seen on this new Barbecoa. It feels instead like a big New York brasserie crossed with a branch of Hawksmoor. Upstairs on the ground floor is a huge, gloomy bar of the sort you’d visit for a stupidly expensive drink on a Friday night after a week of being mercilessly bullied by your boss. The real action is downstairs in a basement space which laughs in the face of economic cold winds and tight accounting. There are gorgeous jade green and ivory porcelain floor-to-ceiling wall panels. There’s parquet flooring and marble, art deco chandeliers you could ride in and, at the back end, a show kitchen boxed off with copper and glass. It’s full of clanking metal machinery for introducing bits of animal to fire.

So is this an attempt to compete with Hawksmoor across the road on Air Street? No, because it’s not competing at all. By which I mean it’s even more expensive. Love Hawksmoor as I do, this is an achievement. At Hawksmoor fillet steak is £11.67 for 100g. At Barbecoa it’s £12.78. Hawksmoor ribeye is £7.88 per 100g while at Barbecoa it’s £9.05. Sirloin is even further adrift. Both use British beef.

It’s a mixed bag of a place. Service is brisk, indeed so brisk that the food arrives before we’ve managed to choose our wine. (More about the bloody wine later.) Waiters keep asking us to name our favourite dish, as if it’s a gastronomic version of Sophie’s Choice, only more harrowing. It’s the kind of question which makes me want to shout: I hate them all. Though I don’t. Pork scratchings, big, warm, slightly oily planks of the stuff, come with a spicy apple ketchup and demand to be eaten quickly.

There’s a whipped butter flavoured with chicken which would be great smeared on almost everything – Michael Gove where are you when I need you? – apart from the dense, clumsy sourdough it’s served with. The pickled chilli, ginger and yuzu mayo accompanying crispy squid is punchy and encouraging, but the squid itself is chewy and underseasoned. A ceviche of scallops and stone bass is let down by both clumsy knife work on the overly thick fish and the bullying presence of grapefruit. All of this is unforgivable in a dish costing £13.

At the main courses, the winners are the sides: broccoli is given a reason for existing by a hefty pelting with miso and almonds. There are thick-cut but properly fried chips. A dish of corn bread layered with cheese and ’ndjua, that soft spiced salami, is drunk food served to you before you’ve quite got there. There’s a butch rémoulade with my St Louis ribs. The meat itself, two thick-cut lumps of bone-in pork belly, is dense and relentless. A fillet steak comes slathered with a duvet of a béarnaise that needs to be scraped off. It lies on top of an inch-thick lump of industrial-strength bread that no one will ever eat. A sawn-through bone filled with marrow is served tepid so its contents are starting to coagulate. Bone marrow must be served hot or fed to the dog.

The bright spot is dessert. The menu of sweet things is a serious piece of work. There’s a “Snickersphere”, a chocolate dome enclosing salted caramel, peanuts and ganache. There’s a lemon meringue pie, a peanut butter cheesecake served in a glass with a mess of cherries at the bottom, a killer brownie with booze-drenched raisins, and a list of cheerfully infantilising sundaes.

And if this had been the last memory of Barbecoa I might have left there, wincing at the prices but humming the desserts. But it wasn’t. The first wine I choose, from a list that accelerates from just about affordable to “stop hurting me” faster than a Brexiteer reneging on economic promises, is a tooth-numbingly sweet Riesling that the sommelier had first said was dry. I ask him instead to recommend a dry white for £35 or less. He immediately suggests a Vinho Verde, pointing out that both he and it are Portuguese. I ask how much it is. Both I and my companion hear “£20” which makes sense given I’d asked for a bottle for less than £35. Halfway through our starters, it arrives. There’s a bit of hassle getting a wine bucket next to the table and being allowed to pour it ourselves, but it’s a nice enough wine for £20.

Then the bill arrives. The wine is £40. I ask the sommelier to explain. He insists that’s what he had said. I ask him why, given I’d asked for a wine at £35 or below, his lightning-fast first suggestion had been a wine more expensive than that. He has no answer. And that’s why I hate asking sommeliers for help: because all too often crap like this happens; because all too often stumbling through the list is easier, and less prone to cock-ups. The manager offers to discount it, but by then the bill has been paid. We leave. I can only hope the extra £5 helps poor old Jamie Oliver deal with those brutal Brexit cold winds.

Jay’s news bites

■ If you don’t fancy a pre-dinner drink in the bar of lost souls at Barbecoa, pop next door to Fortnum & Mason and the recently opened third-floor bar. There’s a strong drinks and cocktail list and a bar menu including Welsh rarebit and deviled kidneys. Is it cheap? Don’t be ridiculous. It’s Fortnum & Mason, but it is extremely civilised, with leather wing-back chairs, a marble-top bar and a sense that nothing bad can happen here.

■ Fortnum & Mason secret of the week. Go down to the ground floor for 6.30pm and they discount any of the leftover patisserie selection by
up to 50%.

■ The eight-strong US barbecue chain Bodean’s has dropped delivery service Deliveroo. ‘They grab 25% of gross takings,’ says owner Andre Blais. ‘With business rates going up we’re really being buffeted. We were giving a fifth of our profits to Deliveroo.’ Instead he’s setting up his own delivery service with a 20% discount on takeaway food. ‘It’s clear the rest of the industry is watching with interest,’ says Blais. (bodeans bbq.com)

Email Jay at jay.rayner@observer.co.uk or follow him on Twitter @jayrayner1