A lot of the paedophiles I treat regularly use school websites to feed their sexual fantasies

Psychologist Martin Shrewsbury

Behavioural expert Martin Shrewsbury, who has studied paedophile psychology, believes Mrs Allen is right to be concerned.

"It's a standard pathology for people with personality problems," he said.

"A lot of the paedophiles I treat regularly use school websites to feed their sexual fantasies about children."

Mrs Allen says the ready availability of children's photos on the web and the ease with which they can be copied has made paedophiles' lives easier.

"This is all very new. I'm trying to curb it now, before something horrible happens.

Web visitors

"Once the photographs are out there you cannot recall them."

Mrs Allen says there are three sorts of visitors to school websites: children themselves, parents with a genuine interest in finding out more about a school, and paedophiles.

One head teacher who she has persuaded to change his school's policy is John Whitby at Potley Hill Primary School in Hampshire.

"We thought she was making a fuss over nothing to begin with," he said.

"We weren't aware of the things that paedophiles can do."

Mr Whitby has written to the county education officer suggesting that guidelines on the issue need to be more clear.