The use - or misuse - of the internet and email for pranks and hoaxes may scare users away, according to a leading psychologist.

Cary Cooper, professor of organisational psychology at University of Manchester Institute of Science and Technology, said that there was a particular problem with emails that were forwarded beyond the limited group of people for whom they were intended.

"Unfortunately you still get these horror stories. And the more that this happens, the more people will tend to get worried about using email as an informal medium," said the professor.

"We may even go back to using the phone call or face to face meetings in cases where we are worried about a message ending up in the wrong hands," he added.

A case last week featured 'the naked civil servant'. A 'friend' posted a picture on the web of Stephen McPherson playing strip poker.

"Tell Him To Marry Me" was the title of the page and viewers were encouraged to email Stephen and get him to tie the knot with the 'friend' he claims he only met twice for a drink.

But Stephen's compromising picture was soon winging its way around the globe to places as far flung as Singapore and Australia.