Lima, 31 Rathbone Place, London W1

Lima's main dining room, designed by Eric Monroe, is all muted beige enlivened with a busy mural (Arved Colvin-Smith)

What do we know about Peru? "El Condor Pasa", Incas, Machu Picchu, Paddington Bear, Mario Vargas Llosa and guinea pigs. Only the last-named, however, has any connection with cuisine. Guinea pigs are popular lunch treats on the Peruvian sierra, charcoal-roasted and served with garlic and chilli. (All those years you watched your children's piebald pets in their cages, nibbling lettuce and twitching their noses, and you never thought of them as a bite-size snack? Have you no imagination?) Also traditional are boiled or mashed potatoes, corn tamales wrapped in banana leaves, and ceviches of seabass, scallops or crayfish. And that's about it for Peruvian nosh – or was until recently.

Suddenly nouveau-Peruve is all over London: there's Ceviche in Frith Street, Soho; Tierra Peru in Islington – and now Lima, a collaboration between two entrepreneurial Venezuelan brothers, Gabriel and Jose Luis Gonzalez, and Virgilio Martinez, a Peruvian chef who owns Central, the highest-profile eaterie in the Peruvian capital. After much to-and-fro-ing across the Atlantic, they've opened this colourful boîte in Fitzrovia, in an attempt (Gabriel tells me) "to bring to London what's happening in Lima today".

The first thing they've brought over is colour. The exterior is a lovely Inca blue, the main dining room, designed by Eric Monroe, is all muted beige enlivened with a busy mural. And the dishes, as we'll see, are a visual gallimaufry of their own.

We started, of course, with pisco sours. People speak nervously of pisco sours, as if they induce madness, like absinthe or mescal, but they're only South American grappa gussied up with lime, syrup, bitters and egg whites. The Lima sours are fabulous, though – salty, limey and frothy all at once.

The menu starts with eight small dishes that mingle classic ceviches (fish marinated in citric fruit) and tiraditos (cuts of raw fish somewhere between sashimi and carpaccio) and causa potato dishes, with more familiar hors d'oeuvres: duck with foie gras, artichokes with fava beans. My salmon tiradito, tenderised with tiger's milk (a concoction of lime, ginger, coriander and herbs) was smothered in rocoto pepper, given a line of green samphire and a lick of ginger. It looked gloopy, but tasted sublime, the salmon's flavour miraculously intensified as if it had been surreptitiously having sex under its duvet of orange pepper.

Louise's braised octopus with olives was an extraordinary sight: four seared octopodal lumps served kebab-style on a bed of yellow quinoa grains, accompanied by what seemed like a dozen blobs of chocolate. In fact, they were 'bubbles' of botijqa olives – densely tasty, as though a pound of olives had been put through an assertiveness-training course. It was a terrific, palate-astonishing starter. I just wish there had been more of it.

Around us, I couldn't help notice, other dishes were similarly striking to look at: a sea bream ceviche as pink as a fairy's armpit, duck crudo served like a tiny island with yellow sand and cress foliage, a pink sea-bass causa on a green slab of avocado with dots of yellow potato purée. I don't know when I've seen food so beautifully arrayed – like a series of Dufy watercolours. I also couldn't help notice the smartly-dress Hispanic couple at the next table who snogged energetically all through their starters. In some inscrutably hot-blooded Latin way, Lima conveys a distinctly erotic charge.

Main courses were less exciting because they were more familiar. There are only six dishes to choose from, three fish, three meat. Louise's confit of suckling pig was essentially pork belly, beautifully roasted, with 'Amazonian cashews' on top, fat lentils in a bed underneath and a counterpoint of pear purée. It was pure piggy comfort food, unctuous and yummy. My lamb shoulder had been braised in a coriander and pisco jus that rendered it amazingly soft, the meat meltingly fibrous, while a sideshow of poached white grapes on black quinoa offered a tasty contrast.

Puddings brought yet more imaginative taste combinations. Chanchamayo coffee ice-cream, flavoured with honey, sat on a simple bed of coconut powder minimally flecked with olive oil, and was lovely. My plate of 75-per-cent cacao porcelano with mango and herb granita didn't quite find a harmony between chocolate and fruit, and the blue potato crisps that divided the plate were taste-free distractions.

We ended the meal in a flurry of potent digestifs – a coffee with pisco vanilla, cognac and orange peel, a sweet hybrid of Cointreau and amaretto with cherries drenched in almond essence – and agreed it had been well worth travelling all the way to north Oxford Street to encounter modern Peruvian cuisine and be startled by its flavours, its zingy colours, its unexpectedness, and the charm of the waiters. And (thank God) not a guinea pig in sight.

Lima, 31 Rathbone Place, London W1 (020-3002 2640). Around £140 for two with cocktails and wine

Food ****
Ambiance ***
Service ***

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

Side orders: Latino lovers

Ceviche

London's other new Peruvian eaterie – and already much-loved. Try 'Don Ceviche', chunks of seabass marinated in lime juice and Amarillo chilli tiger's milk (£7).

17 Frith Street, London W1 (020-7292 2040)

Viva Brazil Churrascaria

For a child-friendly, laid-back Brazilian experience, where carvers move from table to table, offering over 15 select cuts of barbecued meat.

87-91 Bothwell Street, Glasgow (0141 204 0240)

Gaucho

Popular Argentinian chain serving excellent cuisine. Try the Tira de Ancho, spiral-cut, slow-grilled rib-eye steak with chimichurri (£31.95).

21-22 Park Row, Leeds (01132 461777)