Taqueria, London W11

"I haven't used one of these before," apologises the waitress, as she punches in the correct amount of £73.40, which, under the circumstances, still seems rather a lot.

I doubt that the people behind the Cool Chile Co, importers of Mexican products, have run a restaurant before now. A hugely popular stall in Borough Market, yes, but, as I imagine they are learning very quickly, it is not quite the same thing.

Here, there is an all-pervading air of well-meaning amateurism, although on this moderately warm summer evening, I for one am grateful for any air at all. The restaurant is still and stuffy, in spite of windows flung open to the street, and a large fan whirring unconvincingly in a corner. The lack of air-conditioning seems an unfortunate oversight, especially with an open kitchen pumping out heat. A smoothly modern tortilla-making machine occupying one of the three adjoining rooms makes me hot just looking at it.

This doesn't stop Taqueria from being filled to overflowing with enthusiastic Notting Hill types in low-slung jeans and Indian cotton tops, Palms and BlackBerry devices at the ready. There is even a queue of people on the pavement waiting to get in.

What draws them, apart from the novelty of eating tostados and tacos and drinking tequilas and Margaritas, is the pricing policy. Said tostados and tacos run from £3 to £4.50, while snacks, sides and puddings kick off at £2. The decor is similarly economical, with its dark floorboards, pale walls, easy-wipe tables and pre-loved wooden dining chairs. Overhead hang five black metal starbursts in an orgy of 1960s kitsch. I pray for them to magically transform into revolving ceiling fans. Alas, they remain fixed and silent.

When the food starts coming, the prices don't seem quite so small. Dishes are miniaturised, with many of them arriving in scaled-down white shallow bowls that could easily be mistaken for ashtrays.

A ceviche of seabass "cooked" in lime (£4.50) is remarkably tasteless, the fish bland and unseasoned, and the lime barely evident. The addition of tortilla chips doesn't add much to the experience, being more tough and rubbery than crisp and snappy.

At least two parcelled-up corn tamales (£3.50) of starchy corn masa and shredded beef wrapped in corn husks are filling, if sustenance is all you require from your food. Char-grilled baby gem and endive wedges (£2) served with a thin orange and lime "crema" dressing are rather forgettable, leading me to predict that char-grilled lettuce will not be The Next Big Thing.

And so it goes. The flavours are generally bland, the textures uninteresting, the overall effect steamy and muddled. Where are the juicy limes, the chilli hits, the fresh cheeses, the ripe tomatoes, the sparkling summer produce? Where's the freshness and the fun?

A dish of saucy black beans de la Olla (£2) is pleasant, but a cob of corn with butter, lime and arbol chile powder (£2.50) tastes distinctly unbuttery, underlimed and hugely in need of a fix of salt or pepper or both. Chilli on its own is not enough.

Fortunately there is considerably more character in a fine Mexican Bohemia beer (£3.70) and a crisp, dry LA Cetto Argentinian Chenin Blanc (£14.50 a bottle), from the six-strong Spanish/South American wine list.

So what about the main events - the tostadas (crisp corn tortillas) and tacos (soft corn tortillas)? A beef salpicon tostada (£3.50) of shredded beef mixed with crumbly cheese on avocado is as tough as boots to chew. The tacos - served as two small, soft tortillas topped with various fillings - run from OK to get-me-out- of-here. OK is the chicken tinga (£3.50) of shredded chicken with chipotle and tomato sauce, the first thing to have any zip to it. OK, too, is the mishy-mushy al pastor (£3.50) of shredded pork with chile guajillo and mangled pineapple.

Get-me-out-of-here is the Mexican chorizo and potato (£4.50), a wan, sludgy dish with no burn, no bounce and no point. To finish, the nieves, camomile and tequila and lime sorbets (£3.50 for two scoops), are powdery, crumbly and unthrilling.

The Cool Chile Co still has a chance to do for Mexican food what Brindisa does for Spanish cuisine at its tapas bar across town at the Borough Market. But the Cool Chile Co stall hasn't translated into a restaurant and shop as smoothly and easily.

As it is only their first month, Taqueria might yet get its act together. Or it might not. It may also be that we don't understand Mexican food in this country - certainly we know it isn't crisp tacos under mountains of Monterey Jack cheese - but I'm not sure that these people know how to give it to us, either. Stalemate.

11 Taqueria 139-143 Westbourne Grove, London W11; tel: 020 7229 4734. Lunch and dinner served daily. Around £55 for two with drinks and service

Scores 1-9 stay home and cook 10-11 needs help 12 ok 13 pleasant enough 14 good 15 very good 16 capable of greatness 17 special, can't wait to go back 18 highly honourable 19 unique and memorable 20 as good as it gets

Second helpings: More Mexicans

Mestizo 103 Hampstead Road, London, NW1, tel: 020 7387 4064 Mexican goes upmarket in this smart, modern restaurant, complete with slick bar and shop stocked with dried chillies, corn husks and bottled sauces. Downstairs is a moody, chill-out tequila bar and lounge. Co-owner Marysol Alvarado previously ran Si Senor in Soho, while chef Valeria Cheshistz cooked at Mexico City's Los Panchos. Try the cactus salad, ceviche Acapulco style, or the mole from Puebla.

Casa Mexicana 29-31 Zetland Road, Bristol, tel: 0117 924 3901 At this 19-year-old Bristol veteran, top-quality local ingredients such as diver-caught scallops, corn-fed chicken and organic vegetables are given the Tex-Mex treatment by chef Dave Laurence and his team. The menu is the full enchilada, from quesadillas, nachos and tacos to slow-roasted shredded pork with ancho chilli, and king prawns in a red pepper, almond and coconut milk sauce.

Coriander 22 Richmond Hill, Bournemouth, tel: 01202 552 202 Known in Bournemouth as the place to party, Coriander is one big Mexican tourist fiesta, complete with jugs of tequila and plenty of Mexican beer. Start with tortilla chips and dips or perhaps potato skins with refried beans before going on to burritos, enchiladas and quesadillas. House specialties include Coriander Vesuvius, a spicy tomato and chicken casserole in three heat strengths: medium, hot or 999.

Email Terry Durack about where you've eaten lately at t.durack@independent.co.uk