Welcome to Ethnic London

Ethnic London Tours leader Heather Pickering is not hard to spot at the entrance to Brixton Underground station. She is, as she puts it when I greet her, the only white woman standing there. She is certainly the only white woman sporting a pashmina and bright red fingernails anywhere in the vicinity. We are here for what amounts to a technical run-through before her debut minibus tour of London's ethnic communities, which embarks on Monday from just outside McDonald's at Charing Cross Station. Today we are using London's hobbled public transport system to get around, and we're starting on Electric Avenue.

At 11am Brixton Market is already busy, and no one seems to have much time for anyone who isn't buying, but Pickering is as enthusiastic as a first-time visitor and keen to have her questions answered. At a butcher's counter we come across some pigs' trotters dyed a lurid red. "How do you get that red colour? What do you colour it with?" she asks. The butcher duly produces a jar of red stuff. "Oh, red colouring. Is that all?"

"When I bring the people next week, I'm just going to say to them, look, have a wander round on your own," says Pickering. She is confident that people will be astounded by, and moved to buy, the exotic produce on display, although it's hard to imagine tourists rushing to purchase land snails or the "Fresh, Juicey Goat-Leg's" being advertised with characteristic grammatical licence. There are a few blank spots in Pickering's tour-guide patter on West Indian and African cuisine, and she's still brushing up for Monday. "This dried sorrel is used to make a drink which is very red," she tells me, "which they have at Christmas, apparently." Pausing at a fruit stall, she points out some bananas. "Those bananas are not the ordinary bananas," she says, "they're some other kind of banana." But this is, as I have said, just a run-through, staged for the benefit of a single journalist and a photographer.

"It's all in the notes," says Pickering with a wave of her manicured hand, referring me to the 25 pages of information she gave me earlier.

Outside, the photographer asks Pickering to pose for a picture under the Brixton Market sign, but a very large Jamaican man objects. "You can't stand beside us and take a picture," he shouts. "We will smash the camera up! Get the f***k away from here!" We follow this instruction more or less to the letter, moving along up the street in what might be described as a dignified scurry.

"I find that sort of aggression really quite disturbing," says Pickering. "Do you?" We find a less hotly contested view near the Tube station, before catching a slow train to Tooting.

Yorkshire-born Heather Pickering, whose business card lists such diverse talents as function organising, protocol and etiquette tuition, interior design and "period-house counselling", first got the idea for Ethnic London Tours when running an organisation called Southwark Heritage. "I said, why don't we do a brochure of ethnic London? And all the other local authorities said, 'Oh, what a good idea!'. We got so far with it, but it was taking up too much time." Years later, Pickering dug out her file on London's ethnic communities and conceived the notion of bussing tourists into areas they might otherwise never see, to buy things they might otherwise never buy.

In Tooting High Street Pickering seems very much at home, displaying considerable knowledge of Indian cooking and fashion and the basic ethnic spread of the area, which according to the notes is a "long-established community, encompassing all the major faiths - Sikhs, Hindus and Moslems". She guides me through a succession of spice stores, cash-and-carrys and sari shops. It's becoming increasingly clear that her Ethnic Tour is more of an ethnic shopping excursion, but it's none the worse for that. An intoxicating range of ingredients and foodstuffs both odd and familiar are available, including jars of red stuff for dyeing your pigs' trotters. I am strangely moved to purchase an 11lb sack of rice, which I have to lug everywhere for the rest of the afternoon.

At 2.30pm we finally reach Chinatown (signal failure on the Northern Line), where we enjoy a leisurely lunch of Dim Sum at China City (an additional £7 per head on Monday, optional). Afterwards we take a rather rushed look through some Chinese sweet shops and herbalists. As with all guided tours, the scope of this one is beginning to contract as time runs out. Pickering and I grab a taxi in order to make our appointment at the mosque.

At the entrance to the Islamic Cultural Centre and London Central Mosque, better known to many Londoners as that Big Dome Thing in Regent's Park, Pickering adapts her pashmina into a makeshift headscarf. Outside reception there are two big wooden boxes, one marked "suggestions", the other marked "fatwas". The latter, I gather, may in this sense be interpreted loosely as "questions", a service for those seeking clarification on matters of Islamic law. The mosque is an oasis of quiet, a rather jarring contrast to a day of heavy commerce. In fact, Pickering says, the mosque will not always be included in trips where tourists are seeking less spiritual and cultural insight and more cheap fabric and spicy food. A charming girl who usually does children's tours shows us round. Despite feeling like one of a prize pair of sore thumbs, the mosque proves a bit of a highlight - restful, intriguing and a genuinely new experience.