Shrimpy's, King's Cross Filling Station, London

Where have they all come from? All these hipsters, tiny of beard and large of spectacle? Is there a shuttle bus, bringing them over from east London? Why is that man wearing some kind of shortie pyjama suit? And shouldn't that girl try and cover up some of those tattoos with a pretty scarf?

This week we're in Shrimpy's, which pretty much represents the cutting-edge of London dining, at least for those of us who don't get out much. Look away now, if you are sensitive to any of the following words. Pop-up. Art space. Urban regeneration. Calexican food. For Shrimpy's is – in a move guaranteed to stymie even the most ardent parodists of trendy nonsense – a temporary diner housed in the kiosk of a former petrol station. Marooned in the interzone of high-rise developments behind Kings Cross, the old filling station has been re-purposed as a canalside gallery, bar and restaurant, and rebranded as – hah! – King's Cross Filling Station. Once, this was a notorious red-light area. Now the miniskirted girls are buying, rather than selling.

Last time I queued in this space, it was to pay for pump number four and a packet of Rolos. Now I am threading my way across an al fresco terrace, through what seems to be a staff outing from Perfect Curve, and lining up for a table in the booked-out diner. It's small – imagine, say, a petrol station kiosk that has been taken over by architects. The look is American diner with a quirky urban twist, the counter lined with bar stools but sporting flowers and thrift-store pineapple lamps, the walls painted with naïve primary-coloured motifs, like the window display of a particularly inept tattoo parlour.

But the welcome is warm, the velvet banquettes comfortable and the tables draped in crisp linen. Staff are impeccably turned out, in classic French waiter garb of white jackets and black ties. The formal effect was slightly undermined by our Amazonian waitress's double-decker hairstyle – a bleached white bubble perched atop a dark buzz cut. "I've never been intimidated by a waitress's hair before," whispered Harry.

The men behind Shrimpy's are Pablo Flack and David Waddington of Bistrotheque, who have form in creating arty restaurants, both temporary and permanent. Their chef-director, Tom Collins, has apparently travelled through the Americas, both North and South, in search of inspiration for Shrimpy's menu. It reads well, taking a road trip through Mexico (tuna tostadas; skirt steak with chimichurri) Peru (ceviche with plantains) and the Deep South (sweetcorn chowder; fried chicken; soft shell crab burger) with stopovers in Portugal (salt cod croquettes) and Italy (veal chop with fennel, olives and Sambuca). It's so modish, so directional, you'd want to laugh at it, if you didn't want to order everything on it. The cocktail list, too, is full of come-hither tempters, though the margarita with hot Habanero sauce isn't one of them. And prices are generally far steeper than the diner-like plainness of the setting suggests – starters average around £8, and mains from £16 to £19.

So, time to fuel up. Sweetcorn chowder, too often a one-note blast of creamy sweetness, was well-anchored with salt and spice, and swirls of sour cream and chilli oil to keep things interesting. And Shrimpy's must-have dish – the soft-shell crab burger that had its own Twitter following within days – lived up to its rep, the soft sesame bun char-striped from the grill, the crab's distinctive flavour shining through a golden puffy batter. But tuna tostada – fried tortilla decorated with raw tuna, shredded lettuce, avocado and tendrils of fried onion – seemed to have been put together purely for visual effect, the tostada itself as chewy as an old toenail.

No modern menu worth its salt dares not to offer onglet, or skirt steak, these days. But it was the salt that sabotaged Shrimpy's version, apparently the creation of a heavy-smoking chef. Or one who hadn't tasted the pungently acidic dressing on a green salad, or the overwhelming chimichurri sauce which prompted Harry's gloomy Alan Hansen impression – "thyme, and thyme, and thyme again". If that sauce had been petrol, it would have been heavy-leaded four star, and swiftly withdrawn from sale.

The 50-shades-of-Shoreditch clientele is clearly carb-averse; the menu offers only three desserts plus cheese. But the two we tried were good – particularly the brownies, served in a sundae coupe with chocolate ice-cream.

It's a fun place. We loved the vintage wine glasses, and the penguin-shaped ceramic carafes. And we loved our waitress, whose every movement was performed with such a precise, silent-movie flourish, I correctly guessed she trained as a mime artist. Ah, London 2012. The petrol stations are restaurants, the waiters are mime artists, and the hipsters are out on the street, desperately trying to flag down taxis to take them back east. But maybe taxis don't come this way so much, not since they closed the petrol station.

Shrimpy’s, King’s Cross Filling Station Goods Way, London N1 (020-8880 6111)

Around £55 a head including wine and service

Food ***
Ambiance ***
Service ****

Tipping policy: 'Service charge is 12.5 per cent discretionary. All service charge and tips go to the staff’

Side orders: American dream

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