Ambassade de l'Ile

Yet it doesn't have to be like this. For just £20, you can have a superb two-course lunch cooked by a Michelin-starred chef. Which is probably about the same price you'd pay for your chargrilled bland-burger.

By day, the red-brick building looks terribly respectable - rather like a small provincial library - an image that is quickly dispelled as you step into the surprising, Tardis-like interior. It's Seventies meets James Bond. Here a stylish spy or a disco diva could feel equally at home. This is land of leather - with giant white geometric squares of the stuff mounting the walls.

I was meeting my novelist friend who had just finished a book and who always gets excited at the combination of Michelin stars and Frenchmen (she's eternally single but lives in hope). Windswept on arrival, she scuttled off in search of the loo and breathlessly reported back that it was a cross between a sex shop and a torture chamber - with spooky black walls and gushing little ultraviolet water fountains.

Purple is obviously the colour (no politician worth his salt is currently seen wearing a tie of any other shade) - or it is both serious and decorative. The walls here are aubergine. Deep purple freesias adorn each pristine table. Only the grey-green shagpile carpet seemed at odds with the rest of the room, but I assumed it was post-modern irony.

Service (other than the manager, who seemed to spend the entire meal touching a computer screen in a way that suggested she was administering torture by remote control) was excellent. We were brought a little lacy tower of crispy herbs and vegetables (delicious) and bread that was still warm, while we looked at the three different menus. Predictably, the novelist ran her eyes greedily over the à la carte, but I gently steered her towards the lunch menu.

Choice is limited to two dishes but - as I may have mentioned before - I get flummoxed by too many options. My guest started with confit of chicken and tarragon terrine, which she thought looked like upmarket cat food but tasted delicious. My cappuccino of langoustines was richly intense and played the clever, if slightly disconcerting, visual trick of looking exactly like a cup of coffee.

For an additional fiver, we shared a tarte au chocolat praline with nougatine ice cream that was sublime enough to make us wish we'd ordered one each.

If you're counting pennies (which we all are), then skip the coffee and drink tap water. Try the sommelier's affordable selection of wine or a glass from the most comprehensive collection of Armagnacs I've ever seen.