The founders of a controversial phone app used to send abusive messages in schools has admitted the technology has had teething problems.
Developed in America, the free smart phone app named Yik Yak, connects users in a 1.5 mile radius automatically without the need for registration and allows comments to be posted anonymously.
Headteacher of Highams Park School, Steve Riches, recently sent a warning letter to parents and pupils about the app being used as a means to bully fellow pupils.
Despite the use of mobile phones being banned at the school, staff have reported seeing posts between pupils they described as "offensive, harassing, hate-orientated, harmful, defamatory, probably illegal, and are targeted at named individuals."
Yik Yak was launched in December 2013 by Atlanta-based entrepreneurs Brooks Buffington and Tyler Droll, who aimed to build millions of small communities using "geo-fenced" technology, which automatically connects users with people in their vicinity.
In response to reports of the app being used for cyber-bullying, the company says the registered users must now be 17 or over.
The use of the app is also said to have been banned from 130,000 schools in America, but no such move has been enforced in the UK.
Mr Buffington told the Guardian: "We recognize that with any social app or network, there is the likelihood for misuse from a small group of users, so we have put specific algorithms in place to prevent this from happening.
"We have geo-fenced almost all primary and secondary schools and turned the app to 17+ in stores to ensure the user base is age appropriate and parents can easily block the app on their children’s phones.
"Additionally, the app monitors conversations and posts, and any negative or harmful behaviour will result in the respective user being blocked, or altogether banned from future use.
"We continue to build out this technology to ensure positive interaction, but we are also finding that as more users sign up and start using the app, each community begins to self regulate itself in a positive way."
Mr Riches said he is concerned the use of Yik Yak "can lead to severe cases of bullying and creates tensions throughout the school community."
He was warned his 1,600 pupils not to download the app or to delete it if they have it already.
Many of the messages are believed to have been sent while pupils travel to and from school.