Yeni, 55 Beak Street, London W1F 9SH (020 3475 1903). Starters £9-£17. Mains £21-£32. Desserts £9. Wines from £29

Following a major car crash, there’s usually an investigation to work out what caused it. Was it driver error? Or perhaps environmental factors? At some point, the people behind Yeni, a newly opened import from Istanbul to London’s Soho, may wish to conduct such an enquiry. Because right now it really is a pile-up; the sort that leaves debris scattered across all three lanes, and slows the traffic on the other carriageway to the speed of spilt treacle as they decelerate to get a serious gander.

I am going to exonerate the young team working front of house, who deliver both their script and the often calamitous dishes with a touching grace. Also, I have huge respect for the general manager, who retained a certain dignity when the fire alarm went off and continued to roar at us for a good few minutes. Oh, how she punched that number pad, her fingers moving like she was performing a Liszt piano concerto. For us, the siren came between the main course and the dessert. Even someone as godless as I am is allowed to mutter about the possibility of divine intervention. Maybe this alarm would make dinner stop. But we stayed. It’s called commitment. They’re probably wishing we hadn’t.

So no, it’s not the staff working the room. Instead, one must look to Turkish star chef and newspaper columnist Civan Er, whose Istanbul restaurant Yeni Lokanta has won many awards, and his business partner Cem Bilge. But I also sense the dead hand of a consultant; someone who implored them to bring their faux-rustic schtick to Britain and charge what the hell they like for it, “because those Londoners will swallow anything”. Yeni weds underwhelming, occasionally disastrous dishes with the kind of in-yer-face pricing that gives the entire restaurant business a wretched name.

The problem isn’t that we are used, in the UK, to Turkish food being seriously good value, although it usually is. The many smoky grill houses with which the Turkish community has blessed us, heavy with the scent of rendering lamb fat, are a joy. Nor is it that we look to Turkish food for simplicity. During the many summers I spent in Turkey I fell in love with the kebabs and crisp-crusted lahmacun served up at Fethiye’s bus station cafés. Still, there’s always room for a more evolved take on such a culinary tradition. And yes, here’s the dining room for it, with its Aegean turquoise tiling, its hanging globe lamps and its white brick walls which are almost as distressed as we are by the end. The sad thing is, they never do give us anything evolved or diverting.

Brows start furrowing early when we are told the two of us should order three or four of the starters, mostly priced in the mid-teens, plus two main courses. We are also told “these dishes will arrive one by one”. We are at the mercy of the kitchen. It starts oddly. Turkey has a thrilling way with breads. There are puffed up, sesame seed-crusted flatbreads, and rich, springy oval loaves and more besides. All of that has stayed firmly in Turkey. In common with almost every restaurant surrounding us, they have bought in some serviceable sourdough. We tear at it disconsolately.

Now comes an inoffensive taster of a doughy filled dumpling on a yogurt-based sauce dotted with herb oils. It’s a study in beige, and tastes beige too. These tiny dishes are an opportunity to smack us with flavour, to get us excited. Perhaps they don’t want to get our hopes up. For here come wide ribbons of olive oil-braised celeriac. It’s completely fridge cold, and dotted with brutally acidic bits of unadvertised, coagulating sheep’s cheese. It tastes like something left over from the night before, which may just have had its moment 12 hours ago.

After a lengthy break in which we are presented with a dish we didn’t order, quickly taken away, we get a small disc of beef tartare for £16, with a potato croquette filled with liquid egg yolk. It might have worked if the beef hadn’t been minced to such a paste it could be embraced by someone without the benefit of their own teeth. Again, it is served overly chilled. A kind of relief comes in a cheery dish of scallops with a spiced carrot purée and a dollop of sprightly herb sauce and walnuts. On the one hand the scallops are well cooked, the sauces engaging. On the other, there are only two scallops and it’s £17.

Ah yes, those damn prices. The nadir is the £21 charged for a huge slumping package of muddy-grey vine leaves filled with chickpeas, the sour, bile-ridden tang of labneh and more leaf mulch. I stare at the dish, then mutter to my companion: “We’d better get the vet in; that cow’s not right.” We try to eat it, really we do, but it’s less food than a traumatic experience designed to be character forming. It departs the table looking like a rugby field at the end of a vigorous game on a wet winter’s day.

Apparently, the star dish is the “roasted beef ribs, isot pepper, cumin, sourdough”. It reads well, as it should for £26. I’ll have to take their word for it on the roasting. What arrives are ravaged strands of the sort that come with long braising, seemingly mixed with quantities of sticky jus. The other flavourings are obscured. Beneath is a tombstone of now soggy bread. It’s a Turkish dish, but one apparently from that bit of Turkey just to the west of the Pennines. It’s the kind of thing a Lancashire pub would slap on the menu for a tenner and for which we’d all applaud. Nobody is clapping now.

There are just two desserts: a mediocre salted-caramel panna cotta, and some tiny custard-filled doughnuts, which are fine. Both cost £9, which is not fine. The short wine list has nothing below £29. Bizarrely, despite Turkey having a robust wine sector, there’s just one Turkish bottle, as against three from Greece. I don’t want to stoke tiresome regional animosities but I do wonder what they’d make of that back in Istanbul. The rest of the list, mostly priced at £40 or more, is European. At the end, a fellow diner further along the communal table we are clinging to tells me he reads these reviews and senses, “this one will write itself”. It didn’t. I had to do that. But Yeni provided all the material.

News bites

Yeni’s arrival fits with the growth in places offering food from around the eastern end of the Mediterranean. Yotam Ottolenghi’s Rovi, in Fitzrovia, does it very well, and is bang on trend with both live fire cooking and fermentation. It’s an omnivorous menu but vegetables star. Try the sweetheart cabbage with salted anchovy, and the celeriac shawarma (ottolenghi.co.uk/rovi).

Carluccio’s is to trial a more ‘formal and premium’ evening service at its branch in Richmond, south London. According to CEO Mark Jones, they will introduce new tableware and up the vegan offering. This follows the closure of 35 sites, under a company voluntary agreement (carluccios.com).

A few Louisiana-influenced restaurants are marking Mardi Gras. Newcomer Bayou Bar in Tooting is holding a crawfish boil on 5 March. Meanwhile at Jacob Kenedy’s Plaquemine Lock in Islington there’s live music, special menu items and a general ‘party vibe’ on 3 and 5 March (facebook.com/bayoubarlondon; plaqlock.com).

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