Pupils who have taken to wearing a blue wristband to pledge their support for a government-sponsored anti-bullying campaign are becoming the target of bullies, campaigners said today.

The wristbands, which have been championed by David Beckham, Kelly Brook and Bono, have also become a sought-after fashion item. The website eBay is currently advertising 25 for up to £21 a go.

Julie Oakley, the founder of Bullywatch, which supports families of the victims of bullying, said: "Kids who wear the wristbands have become natural targets.

"There has been a lot of interest in them because they are rare, and have become valuable. They are sought-after in the same way as new trainers.

"It's totally sick that something designed to help fight bullying could be used in this way - it completely defeats the object."

Michelle Elliot, director of child protection charity Kidscape, told the Daily Mirror: "We were afraid that they would make kids wearing them a target.

"Bullies will find any excuse - but I'm disgusted something with such good intentions should end up being abused like this."

The wristband campaign was launched by Radio 1 at the beginning of the anti-bullying week on November 21.

Launching the first Anti- Bullying week, the schools minister, Stephen Twigg, said : "Bullying creates misery for thousands of children and it is crucial that they know they are not alone.

"Wearing the band will give young people the opportunity to make a visible commitment that they are not prepared to tolerate bullying and will stand by their friends."

However, school pupils were quick to spot the reality of wearing the wristbands. Writing on the BBC's Newsround website, Rosie, 13, from London, said: "Ugh... I'm sorry, but in one school near me, it's made it a whole lot worse. Bullies are stupid, everyone knows that, and so they came up with a stupid idea.

"They basically thought 'Hey! Everyone who's wearing a wristband must be scared of bullying!' So they decided to bully the people wearing wristbands. So, it's made a difference, but not a good one."

But there was also support the for campaign. Izzy, 12, from Bath, wrote: "I think the fact that all the celebs are wearing the wristband will make a difference, because it might make people realise that it's not cool to bully."

However, a third, Shona, 13, from Norfolk, said: "I didn't even know it was anti-bullying week last week, and neither did the bullies at my school."