Single item restaurants are everywhere these days – I applaud the attention to detail and the passion that it requires. But if you’re betting your whole restaurant on one throw of the dice it has to be perfect. Le Relais du Venise just isn’t.

Based on the Parisian original, this outpost near Marylebone high street is a little piece of France. The waitresses are appropriately attired, the tables are tiny and jammed together and the décor is perfect – it could be Pied du Cochon behind the Louvre in Paris. The menu is very simple, just one choice – they serve an entrecote steak with the house sauce for £21. It comes with a simple salad as a starter and piles of French fries. The wine list is almost as short with three or four red and a token white. I opted for a medium priced Bordeaux and was pleasantly surprised.

The salad is lacklustre. It’s some simple leaves, doused in a mustardy French dressing with a few walnuts. You don’t get the feeling that they’ve taken a lot of care with it. The bread was also a bit anonymous; it missed the texture and flavour of the authentic French stuff.

Next came the main event. Don’t be alarmed at the portion size, it’s served in two stages. You get half the steak to eat while they keep the remainder warm – once you’ve cleared your plate they bring out the rest and top up your chips. The steak was blue, as ordered, but the grill wasn’t hot enough to give it a decent char. The beef didn’t really stand out and the peppery sauce could have done with more kick. The chips were perfectly nice but are a little under-seasoned.

For dessert they allow you a little more freedom, it’s French classics from Tarte au Citron to Creme Brûlée I had a ‘Gâteau du Relais’ – a thick gooey slab of something like a ganache and a lighter, brownie style cake. Both were delicious.

The service was polite and friendly  – I almost missed the disdain you’d get from a proper Parisian restaurant. What lets them down is the food – if you only do one thing, it has to be incredible. The cooking and ingredients were just average – you’d get a similar quality steak somewhere like Café Rouge. When there’s challengers like Flatiron a few minutes’ walk away it becomes very difficult to justify a visit. As a concept, it’s fun but as an experience, it doesn’t really deliver.