Four human guinea pigs have volunteered to do just that as part of a bizarre experiment to test whether it is possible to survive using only services available on the Internet. The volunteers each will spend 100 hours in separate cells at a secret location in central London, trying to feed, clothe and entertain themselves using only the Net.

Apart from the Internet -- and deliveries ordered using it -- the four will have no other contact with the outside world, though interested Internet users will be able to check how they are faring via a website on which regularly updated snapshots will be posted.

The study is being conducted by Helen Petrie of the University of Hertfordshire, an expert in human-computer interaction. ``Everyone is talking about the Internet, but no one has put it to the test like this. The results promise to be fascinating,'' said Petrie.

Thefour -- men and women aged from 30 to 67 -- were selected for their varied ages and levels of Internet experience. They were among hundreds of volunteers who responded to an ad placed in a national newspaper on behalf of MSN, Microsoft's Internet service.

The successful applicants were promised their own PCs and œ500 to spend on items such as food, clothes, CDs and even microwave ovens for survival by Internet. MSN's product manager, Nickie Smith, commented: ``There's been a huge explosion of interest in online shopping over the last six months. We wanted to put the current Internet services to the test.'' Last year Britons spent œ 406 million on Internet purchases, double the amount spent in 1997.