Trullo 300 St Paul’s Road, London, N1

Trullo certainly has consistency going for it. Unfortunately, that's just turned the Italian into a repeat offender

Allow me to start with a little adventure in the abuse of logic. Recall, if you will, the last time you were at a dinner party, and while advancing an argument in which you have an obvious stake – the immorality of racism, say – some impish goon at the other end of the table admonished you with, "You would say that."

Roughly translated, that means: "Shut up, you're boring." But just because you have an obvious stake in an argument doesn't make it wrong. So don't apologise about being predictably right. The fact that you advocate an argument consistently is a virtue in you, not a vice in the argument.

But what if you are wrong? What if, starting from a false premise, you make the same mistake over and over again? In that case, it may have been better to keep quiet. You have been making what is termed an iterative error, and mistakes are less forgivable when made repeatedly.

That, alas, is what Trullo is. It is a well-intentioned, inoffensive, reasonably priced, iterative error. With a few exceptions, its menu is a series of repeated mistakes. The mistake is to provide dishes that are either over-complicated or simply deficient in strong flavour. Take the slow roast mutton, Jerusalem artichoke, cob nuts and anchovy dressing, at £7 joint equal as the most expensive of the four antipasti on offer. This dish is like a team of enthusiastic and talented youngsters who lack an inspirational captain. It has no driving force, no leader. The mutton is OK, but the anchovy dressing is engaged in permanent violence against it. "Quite complex but ultimately flat," is the report from Virginia, whose birthday we are celebrating.

The salt cod with coco blanc and salsa rossa – little beans, one grade up from haricot, and a tangy, parsley-infected green sauce – is fine but unspectacular, and the Romanesco fritti with melted Gorgonzola would be overly dignified by comparison to a soggy cauliflower cheese. Then, suddenly, we are confronted with a bolt of magnificence: the pappardelle with beef-shin ragu – tender ribbons of beef with an intense tomato flavour. This raises expectations unreasonably, because, like the décor, the unpretentious cutlery, and the inglorious location – we are, in essence, an adjunct to the Highbury roundabout – it is bold, effective and simple.

But most of what comes after is just plain simple. The tagliatelle with wild mushrooms is a dullard's delight. The risotto with purple sprouting broccoli, anchovy and chilli tastes of all the things it ought to taste of, but excites little. Jack, a man of extreme intelligence and honesty, whose birthday we are also, incidentally, celebrating, describes it as "hot but featureless". Two slip soles are beautifully cooked and good value at £15, but decorated by a lifeless braised chicory, none the better for an oregano dressing. The Middle White pork chop, sourced from a butcher on the nearby Essex Road, is straightforward rather than special, though the grilled Italian peppers and violetta aubergine with it, a kind of glorious pre-baba ghanoush, are plangently smoky and delicious.

The pear sorbet is lazily presented; so, too, is the hazelnut ice-cream, but it is excellent value at £4, and has a warmth to it no ice-cream ought reasonably to manage. One of the charming waiters – the service is outstandingly cheery and well-informed – tells us about the Ubriaco (that is, drunken cheese) and though it arrives somewhat sparse for £7, it goes rather comfortingly with a 2009 Donnafugata, good value, too, at £26.

This restaurant is a joint venture between Tim Siadatan (of Fifteen, St John and Moro) in the kitchen and Jordan Frieda (River Café, among others) front of house. It attempts to be a north London Uniqlo of food (albeit Italian): plain and simple, confidently cool, and demanding frequent revisits. Their method is endearingly uncomplicated: navy-white colour scheme, superb waiting staff, unfussy presentation and a short, daily changing, menu (though if I'd turned up with my vegetarian parents, we'd have lasted barely two minutes, so limited are the options).

Such a formula makes it trendy among trendy types. But I have to report that, shin ragu and hazelnut ice-cream aside, it felt as if each dish made the same mistake, promising much but delivering little. It is reasonably priced, I guess, but long before my girlfriend declared her adoration for the panna cotta, I'd made a note to celebrate my own birthday someplace else.

5/10

Scores: 1-3 stay home and cook, 4 needs help, 5 does the job, 6 flashes of promise, 7 good, 8 special, can't wait to go back, 9-10 as good as it gets

Trullo 300 St Paul's Road, London N1, tel: 020 7226 2733 Dinner, Tues-Fri; lunch and dinner, Sat; lunch, Sun. £210 for dinner for four with two bottles of wine and four glasses of dessert wine

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