Osteria Dell'Angolo, 47 Marsham Street, London SW1

Cut to: Interior. We could be in a business hotel in any part of the Eurozone. The dining room is smart but characterless, with a peach and amber décor reminiscent of the 1980s. The crowd is monied and international. At a table, a scruffier couple is bickering.

"Why are we here, exactly?" asks the man, who seems remarkably peevish, considering he is sipping champagne that someone else is paying for. "Because it's the only bloody restaurant in London that has opened all month", replies the oddly alluring woman opposite him. We notice that she is unsuccessfully trying to hide a small notepad under the table. The man sighs, and orders another drink.

There's nothing like dining in the shadow of the Ministry of Justice to make you feel like you're a character in a spy thriller. Westminster newcomer Osteria Dell'Angolo has the kind of bland, complacent atmosphere you get in movies just before Jason Bourne comes bursting in feet-first through the window. Given its proximity to the Home Office and adjacent ministries, it's ideally located for a spot of lunchtime intrigue, with alcoved tables perfect for off-the-record briefings and covert back-stabbings.

On a Saturday night, though, its regular constituency is replaced by civilians; well-heeled locals and visitors who look like they've been directed here by their hotel concierges. The décor, with its polished marble, patrician stud-backed chairs and rag-rolled walls (or maybe sponged – how quickly one forgets) is blandly comforting. "It feels like we could be anywhere in the world, apart from a smart new restaurant in London," as the complaining man (aka Harry) observed. All the character comes from the food, which is inspired by head chef Michele Brogi's upbringing in Tuscany's Valdarnese Valley.

Brogi's style is more rarefied than the peasant-inspired school of Tuscan cooking associated with the River Café and its imitators. The menu is full of intriguing dishes, most of which sound a great deal better in Italian than they do in their English translations.

Take my starter, "soppressata di maiale secondo la tradizione dei miei genitori". Doesn't that sound better than "my parents' brawn", which is how it is glossed on the menu? It got even worse, when our waitress introduced the dish with a murmured "the pig's head..." Wah! Can't we stick to calling it brawn? Still, whatever secrets Brogi's parents brought to the pressing of their pig's head, the result was great, with a wonderfully velvety texture and a delicate flavour pointed up by a zingy salad of grated endive.

There's a line-up of interesting-sounding pasta dishes, including stretched ravioli stuffed with burrata cheese and duck ragu, and "guitar-cut" spaghetti with shellfish. From it, Harry chose the most obscure, bigoli – a kind of supersized spaghetti, tossed with anchovies and fried sage in a "soup" of white beans. The pasta, obviously made in-house, had a springy bite, but the dish was surprisingly bland, given that anchovies were allegedly involved.

Cut to the main courses, and suddenly things went wide-screen and into Technicolor. Sea-bass braised with mussels, baby carrot and leek was brought to table in a cast-iron casserole, and served with all the solemn ceremony of a Japanese banquet, while Harry's lamb sweated under its silver cloche. Both the bass and the lamb – roasted neck of, served with puréed apple – were immaculate.

The clearing away of each course prompts a fresh round of table-sweeping by the studious-looking staff, who evidently take their job very seriously – maybe a bit too seriously, if you just want to have a nice relaxing dinner. If they seem suspiciously well-drilled for a relatively new restaurant, it's because the Osteria comes from a stable of pedigrees; owner Claudio Pulze is one of London's most prolific restaurateurs, whose previous successes include Zafferano.

From a mainly Italian wine list which offers a wider than usual regional variety, and a two-page credit-crunch selection priced at less than £35, we were steered towards a 2007 Pinot Nero from Trentino-Alto Adige (at £35, just nosing out into the bugger-the-credit-crunch selection). The complaining man from scene one returned to complain that the glass of Terre Arse Marsala he took with his cheese was musty. Nevertheless, the oddly alluring woman let him share her zuppa Inglese, whose custardy depths and big blousy flavours were far more exuberant than anything that had gone before.

Our bill came to around £50 a head, though it felt odd to be doing the whole chip and pin business, rather than just signing to add it to our room bill. In an area short on decent restaurants, the Osteria should do well. If you're looking for a place to wine and dine a senior civil servant, it would be perfect. It's just not quite right for an intimate dinner à deux. Still, mission complete. Fade to black. Sound of bickering fades out under credits.

Osteria Dell'Angolo, 47 Marsham Street, London SW1 (020-3268 1077)

Food 4 stars
Ambience 2 stars
Service 4 stars

Around £50 a head, including wine and service

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