The modern trattoria derives from the famous Terrazza in Soho's Romilly Street, started in 1959 by Mario Cassandro and Franco Lagattolla. It was a desperately groovy but authentically Italian joint frequented by shrieky socialites, photographers, visiting film stars and the first wave of media tarts. It set the gold standard for trattoria life: a local, pop-in-for-supper restaurant, cheap and jolly, full of fiascos of chianti, elongated pepper grinders, joshing waiters and an aproned Neapolitan Mamma pinching your cheek and encouraging you to eat, eat or you will never find l'amore.

Il Baretto is in the heart of Marylebone restaurant-land – the wonderful Anglo-Indian Trishna is next door, the Galvins' flagship round the corner in Baker Street – and promises old-fashioned trattoria virtues. Before its current incarnation, it was the home of Giusto, and before that La Spighetta: it's so Italian you half-expect to see hair sprouting beneath its awning. The upstairs bar is tiny and cute. Downstairs, the welcome from the staff is pure theatre, as the maître d' and waiters vie with each other to welcome and seat you.

Sadly, it doesn't last. You look around the oddly shaped basement, with its blank walls and long mirror and don't feel terribly cheered. In the corner where we sat, the walls were faux-marble, and hung with images of Anita Ekberg from La Dolce Vita, but the tables were too large, and the lighting too harsh, for impulses of romance. Black banquettes strike an austere note against the pale wood. "I like an Italian restaurant with a white tablecloth," said my date, Virginia Ironside, The Independent's beloved agony aunt. "And some bread and olives would also be nice." She looked around. "A restaurant should make you feel loved, and I don't think this place does."

The menu was peculiar. On the two pages of antipasti and pasta, grills and al forno stuff, several dishes were printed in red. Why? They didn't seem vegetarian or likely to contain nuts. Did they involve endangered species? (But which bit of pizza bufala is endangered? The buffalo?) The waiter explained the red bits were "to break the monotony of the page".

The monotony of the dishes needed a jolt in the gonads too. I looked down the list of predictable calamari, carpaccio, linguine-with-clams, and "meat ravioli" (which meat?) and asked the waiter to recommend something that demonstrated the kitchen's unique skill. He suggested the swordfish steak. I said it was hard to do anything very meaningful to a swordfish. OK then, he said, the penne all'anduja (molto piccante), namely pasta with spicy Calabrian sausage. It came. It was nursery pasta with hot sauce, and that was all it was. The sausage was dispersed across the pasta rather than sliced, making me wonder if it was just sausage-meat given a whack of chilli. I could have made it myself at home while watching the tennis.

Virginia eyed her seabass carpaccio with suspicion. "It doesn't look very appetising," she said. "The sea bass isn't waving at me but drowning." It was drenched in olive oil. Even the colour was wrong. Thin-sliced pink fish on a white plate looks fine; surrounded by a yellow oil slick, not fine.

The oven-cooked mains all dated from 1959 or so: five pizzas, home-made lasagne and cannelloni. From the grill, you could gorge on tuna steak, langoustines or veal paillade. These dishes, I complained, don't seem to offer a very complicated dining experience. No, said the maître d', "They're very simple – and delicious."

"If it's so simple," said Virginia tartly, "why isn't it cheap? That pasta dish should be £4.50, not 12 quid." And that's when I realised why I felt annoyed with the place. Its menu and cooking style are indeed that of an old-fashioned trattoria. But its prices would be more appropriate to the River Café.

Things improved with her roast lamb cutlets with herbs, so pink and tender, she ate them with her fingers. "Usually when lamb is rare, it's chewy," she said. "This is lovely. They must have marinated it in oil and rosemary for ages to make it so tender." My spiced baby chicken alla diavolo required (according to the menu) a special 25 minutes to achieve perfection. When it came, it was a perfectly roasted – and utterly ordinary – polletto, with a smear of spicy marmalade on the crisp skin. "It's OK," said Virginia sadly. "But it's not raised up to any interesting degree, is it?"

We shared a watery panna cotta with raspberries, served on a rectangular plate. Like the colour-coordinated menu, this seemed an empty gesture towards sophistication. Il Baretto is like that all over. It's actually an old-fashioned trattoria, serving OK-but-dull food, but gesticulating wildly that it's something far more special. Keeping It Simple is all very well. Sometimes, though, it comes across as Not Trying Hard Enough.

Il Baretto, 43 Blandford Street,London W1 (020-7486 7340)

Food 2 stars
Ambience 2 stars
Service 3 stars

About £100 for two, with wine

Tipping policy: "Service charge is 12.5 per cent discretionary. All service charge and tips go to the staff"

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