Showing me around his £22.5m Mayfair home, my host is incredibly welcoming. “You can come any time,” he says. “Feel free to do whatever and go wherever you like here.” It is a delightful thought as I admire the huge circular first-floor drawing room, with its lofty, corniced ceilings and fine silk wallpaper.

Trouble is, the house doesn’t actually belong to my host, Michael, a tall, unshaven artist in his early twenties, who has a patterned, tasselled woolly hat jammed tightly over his head to keep out the cold. As a squat, 39 Charles Street and, behind it, 39A Clarges Mews, has no working central heating — and my guide is a member of an anarchistic collective of painters, sculptors and musicians that has taken over some of the capital’s most exclusive houses.

These are not exactly the homeless, at least not in the usual sense of the word. These squatters have private-school backgrounds, glamorous wardrobes and a taste for exquisite surroundings. They keep warm in fur coats and drink from Starbucks mugs. And they’ve just traded up — after being evicted from their previous squat, a £6.25m, 30-room, six-storey townhouse in Upper Grosvenor Street, in November.

According to the latest figures from the Department for Communities and Local Government, there were more than 760,000 empty homes in England in 2008 — including a surprisingly large number in the swankiest parts of the capital. The Da! Collective claims its Mayfair takeovers are helping to highlight the plight of “abandoned” buildings in the capital. So how did they get in? “Through the roof,” explains one turban-clad bohemian.

Members of the group describe themselves as a new breed of squatters, one that respects their chosen homes’ heritage. To make his point, as we approach the historic part of the house, which is Grade II*-listed and marked with signs on the doors describing it as a “leave-no-trace-space”, my guide tells me: “We can’t leave a mark here. So no smoking or drawing on the walls.”

The need for such precautions becomes clear when I see the other rooms used by the squatters for living and working, where the aim appears to be to draw on as many walls, in as many colours, as possible — giving them the air of a school art department.

The house has been filled with the squatters’ haphazardly gathered furniture, including striped beach chairs and lecterns. A stack of mattresses serves as seating for talks during the day and sleeping at night.

Now the economy has gone south, squatting is firmly back on the agenda. In December, a group of a dozen or so squatters, blaming the economic downturn, took over a four-storey, £1.75m, Grade I-listed Regency mansion in Brighton, once owned by Princess Louise, Edward VII’s daughter. A disgruntled neighbour described them as “your typical middle-class dropouts”. Other slightly less grand houses elsewhere in the country have also been taken over. It is all reminiscent of the last recession, in the early 1990s, when the Sultan of Brunei’s house in west London — which had pictures of its owner with the Queen decorating its hallways — was occupied.

Despite the sumptuous rooms, this bunch aren’t here only for the posh address: they like to see themselves as an enlightened artistic movement and have set up a “temporary school” in the house, with talks, lectures and workshops on everything from laughter and life drawing to Tibet and climate change. There is even a session on learning Omaha poker.

All the activities are run by volunteers — “Anyone can come and talk about what they feel passionate about,” I am told by a girl with gold leaf glued to her face. Within a few hours of arriving, I have been given a juggling lesson and an invitation to labyrinth building (despite one of the squatters’ best efforts to explain, I never worked out what it is) and attended a talk on anarchy (the besuited lecturer was recording the talk for his files — apparently, even anarchists keep records).

Surprisingly, there is order, of sorts. As well as regular tea breaks in an office-like space with timetables and floorplans of the house, the fur-clad, Marlboro Light-smoking youths have dinner at 7pm every night, with one of the live-in squatters cooking for whoever’s hungry. A few sleep over, but anyone can come as they please.

The squatters also put great care into their choice of property, watching it for three months before moving in. It was bought in April 2007 by a company called Timekeeper, which left it empty while waiting to obtain planning permission to carry out work there.

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