My first experience of Mexican food came in the late 1980s. I was 19 and in thrall to a short and utterly corrupting liaison with a much older man, a comedian in his early thirties. Once, after a day lying in bed watching him watch himself on video, he took me to a burrito joint in Islington, repeatedly telling me how much he loved Mexican food. I remember thinking that it was stodgy and horrible – although refried beans, guacamole, tortillas and tacos certainly had their place in soaking up the copious quantities of alcohol he was so expert at putting away.

It is here that I must insert the standard restaurant critic’s stance on Mexican cuisine. It is an oft-repeated fact that the most diverse cuisines in the world are Turkish, French, Italian, Indian, Chinese and Mexican. You can’t help wondering whether it’s entirely true when it comes to Mexican: all we ever see of this epic cuisine is pancakes cooked and folded in various ways, and filled with beans, cheese and meat. Avocados, lettuce and chillies also feature.

This Mex hegemony is traditional, but on hearing about Wahaca, a newborn Mexican restaurant, I was determined to be the writer of “good Mexican restaurant shocker” and win myself a prize for the scoop of the decade. I knew Wahaca’s executive chef, Thomasina Miers, had more than done her homework on her extensive culinary tours of the country. On arrival, the place seemed promising: a big, airy basement, done out in exposed concrete and citrus colours, with no fake pueblo styling in sight. The margaritas looked storming (I couldn’t drink one – I had myself a scoop to write) and there was an extensive tequila selection. I waited at the bar for my friend Kev with an alcohol-free hibiscus water, a sort of sweet, floral squash, and a little bucket of furnace-blasted pork scratchings, cooked at such a high heat that all the fat had gone, leaving a pig-flavoured, Quaver-like bite. My expectations rose further. Should I just punch the air now?

Miers won the new and improved, jazzy reality-TV-style Masterchef two years ago. I was one of the judges who spotted her infinite superiority to the other contestants, and even though her zarzuela, a Catalan fish stew, was oversaffroned, it remains one of only two memorable dishes out of the 40-plus I’ve eaten in three years of the show (the other was Midge Ure’s tempura shellfish, of which we will say no more for fear of upsetting Ultravox fans). Miers clearly had a depth of knowledge and understanding that elevated her way above the dinner-party divas against whom she was competing.

And my, she has worked that win to her advantage. Before long, she was doing telly and books and writing lots of food’n’travel pieces about her sensual journeys through Mexico. She wrote a typically purple-prosed piece of food porn recently, describing in great detail the Mexican markets that provided the inspiration for her new restaurant: the “10 types of bean, from speckled to brown-and-white spotted ones”; the corn, “in yellow, white, red and blue hues”; and the “multitudes of different types of dried chillies that line the lengths of the markets”.

A Grinch-like Kev grumbled in, weighed down by his food-snob baggage. “They say all those Mexicans crossing the border into the States come for the economic opportunities, but really they are running away from the food.”

“Yes, yes,” I said, “but this is going to be different. You’ll see.” I waved the in-house magazine, Ola London, under his nose, which seemed to infect him with my enthusiasm. He’s incredibly hard to please, but he liked the pork scratchings.

Two salsas came: one clean and fresh, made with green tomatoes and chilli; another earthier, made with chipotle (smoked chillies) and sweeter red tomatoes. We rubbed our hands and weighed in, ordering largely from the little plates on the street-food menu – a fish taco, tostados, one with mackerel and another with chicken – plus a marinated pork dish, called a pibil, from the larger platos fuertes. It all came at once. “Come on then,” I said. We tried a bit of everything. “How is it?”

“It’s Mexican food, that’s what it is.”

The pork, the fish, the chicken, even the coleslaw we tried on the side – it all tasted of the same non-specific, slightly hot “tasty” flavouring. It was like Marks & Spencer’s ready meals, designed blandly, to appeal to the widest possible range of taste buds. Wahaca seats 150, turnover looks rapid and it’s in a touristy part of town, so I guess they need to. The homogeneity extended to the texture. All the meat was ragged or minced. The fish was bobbly and woolly. A side order of green rice sounded perfect – brown rice, onion, garlic and coriander. But it tasted of powdered garlic and not much else, not even the distinctive nuttiness of brown rice. Corn on the cob was edible, but somewhat undercooked.

It’s cheap here, at the moment, which is a consideration when discussing quality. Wahaca isn’t bad, but with a little extra effort it could be lovely. Where is the fresh ceviche? Why can’t the chicken be laid in chargrilled strips across its bed of iceberg lettuce, instead of minced to an orange squidge? The great Ms Miers can definitely do better than this.

I do believe there is good Mexican food out there. Crazy Homies in Westbourne Grove does great tostados, ones on which you can actually distinguish a fish topping from a chicken one. The food at Wahaca never raised itself above ordinary. (Although, to be fair, the people at the table next to us – industry insiders from neighbouring restaurants – were having a whale of a time. They were also drinking copious beers and cocktails.)

For pudding, we had churros. Now churros I know about. Churros had me dicing with obesity in 1988, when I was in Barcelona being the world’s worst nanny and developing a lifelong love of white spirits mixed with Fanta Limon. After too many of those, I’d have too many of these little extruded doughnut wands, freshly fried, ideally kind of soft, with the thinnest crispy brown skin, drenched in sugar and sweetly bitter cinnamon and served with horchata, a funny kind of nut milk rarely seen anywhere outside Spanish-speaking countries.

They did not have horchata here. These churros were quite hard, without a trace of cinnamon and sugar, and came with a microscopic cup of dense hot chocolate. When I saw them on the pudding menu, a little lump came to my throat and a summer of Barcelona dawns went racing through my mind. But they failed to transport me into great nostalgic reveries – they just reminded me, once again, of that booze-sodden, Mexican-loving comedian.

AA Gill is away

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