A PRAGUE brothel offering free sex and the chance of internet stardom is providing men with a novel style of sexual recreation. The formula of the Big Sister brothel in the Czech capital's Old Town is simplicity itself: entry is free and patrons can choose their playmates from an electronic database.

On any given day, depending on demand, between 30 and 45 young women are available to clients. The world's first free brothel's link to a voyeurist internet sex reality show has proved so successful that its two Austrian entrepreneur owners, who cannot be named for legal reasons, are thinking of expanding abroad. They are hoping their male-oriented brand, marrying state-of-the-art technology with the world's "oldest profession", could soon be replicated in Britain.

To participate in the "fun and games" a punter has to show an ID card or passport and sign a contract accepting that the owners can film the intimate proceedings and use the footage as they please. After a payment of 10 (£7) for the use of a towel and slippers, he can choose a woman. The brothel's database caters for all tastes, and the choice can be made accordingly, based on facial or body image, breast size or linguistic accomplishments.

No sensory stimuli are overlooked in helping a client add to the experience. He is even offered a variety of backdrops, both rural and urban, ranging from flowering meadows to a jacuzzi, an igloo or, for the discerning goth, a scene of Hell. But, of course, all these sexual choices, preferences and selections are really designed to add to the experience for the worldwide viewers of this internet sex reality show.

"Anyone entering Big Sister is immediately being filmed and thousands of internet aficionados can follow their every move from beginning to end from the comfort of their living room," Carl Borowitz, the brothel's marketing director, said in an interview.

The only caveat is that the client cannot cover up his face: any attempt at hiding or disguising the face and the liaison is stopped. But as a consolation prize, the punter is given a complimentary DVD featuring his performance, presumably to show the lads back home.

There are 58 high-resolution cameras operating throughout the building, with three technicians editing the "story line" of the reality show, starting with the couple's first encounter and following it through the opening foreplay to the post-coital cigarette.

Whether the proceedings add a new twist to 21st-century sexual liberation, or just follow centuries-old common sexual exploitation, is not too difficult to answer. But the fact remains that brothels and prostitution are legal in the Czech Republic and this internet sex reality show is being staged, night after night, by willing "freelance" and professional performers.

It is not clear whether the "girls" on the Big Sister's books are hardened professionals or cash-strapped students acting as temporary bit-players. But, as marketing director Borowitz insists, they are all paid well, treated with "respect" and, "with a little extra effort, they could become internet stars".

Their working hours stretch from 6pm to 3am for a monthly salary of between 3000 and 5000 (£2000-£3500) and all the free time they need to pursue other interests during the day.

In spite of the reassuring words, this brothel, with its internet exposure window, still seems to be no more than a place for sad and lonely men to go to escape the disappointments and failures of their personal lives. However, the Big Sister formula appears to be a profitable enterprise, even with the hefty payroll, as the management's expansion plans indicate.

The figures proffered are interesting: since 2005, the Big Sister's internet home page, showing an average of 14 daily performances, has registered 10,000-15,000 hits per day. With a monthly subscription fee of £19, the income from this porn channel adds up to a tidy sum.

Subsidiary rights have been bought by British and Italian porn channels and DVDs marketed under the lurid titles of Sex Hyenas and Prying Eyes are adding even more cash to the Big Sister coffers.

However, Britain's Sexual Offences Act 2003 could pose some problems to any plans to bring the formula to British soil.

For a start, brothels are illegal in the UK. Furthermore, new crimes created by the Act include voyeurism and exposure to sex acts, all of which could apply to the entrepreneurs' idea of linking their free brothel with the internet sex show.