It is one of the fastest growing property trends. Thousands of people around the world do it every week, and an estimated 100,000 Britons have done it at least once. It isn’t a loft conversion or investing in Bulgaria, but homeswapping, where owners take photographs of their homes, post them online and wait for like-minded people to exchange houses with them — at least temporarily.

The desire to swap not just one’s home, but one’s life, is the starting point for The Holiday, a romantic comedy starring Cameron Diaz and Kate Winslet, which opens this Friday. They meet online at a home-exchange website and impulsively switch homes for the Christmas holiday.

Desperate for a change, Diaz’s character, Amanda, swaps her vast Los Angeles villa, which has a gym the size of a one-bedroom flat and a body-length plasma-screen television, for a chocolate-box cottage in Surrey, complete with Aga and Yorkshire terrier. It is home to Iris, played by Winslet, a lovelorn wedding columnist for a national newspaper, who commutes in wellies and cashmere.

It is the seeming inequality of the kind of temporary exchange featured in the film — a tiny British country property for a swanky villa in Hollywood — that is the big attraction of home swapping.

“People are looking for location,” says Caroline Connolly, director of HomeLink, which has 1,300 members in Britain who pay £115 a year to be listed on its website. “It’s about having a base to explore. Most of the homeswappers listed on the website are professionals with nice homes, so you could easily end up swapping a three-bed semi for a villa in Tuscany.”

Maggi and George Pemberton, both retired, have been exchanging their three-bed bungalow near Torbay in Devon for almost five years. It has taken them to Bruges, France and Canada and they have just returned from six weeks in America, spent mostly in Florida.

“We also stayed in a wonderful house in Williamsburg, a colonial town in Virginia,” says Maggi. “The standard of homes in America is very high. It had five acres and a swimming pool. We would never be able to afford to rent somewhere like it.”

The practice began in the 1960s, and there are now homeswap agencies worldwide. HomeLink has offices in 26 countries around the world; Intervac is another popular site, as is www.homeforexchange.com and the American HomeExchange.com, which features in the film.

One advantage of homeswapping — other than the obvious fact there is no rent or hotel bill to pay — is you get to live somewhere with all the trappings of family life: DVDs, washing machine, the internet and teaspoons.

Increasingly, too, the ranks of homeswappers are being swelled by multiple-property owners, who, although they may wish to keep the front door to their main home closed to strangers, are more willing to barter their second, or even third, homes.

“Numbers have probably risen threefold in two years,” says Connolly. “Some people list both their homes, but others prefer to list just their second home. It is also more flexible as you don’t have to swap homes at the same time.” It is not just about one- or two-week stays either: many people are looking for long-weekend exchanges, often with Britain.

But isn’t it dangerous leaving your home to the mercy of holidaying strangers? No, says Connolly — as it is a self-selecting method, serious problems are few and far between.

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