A 17-year-old boy has been arrested by Wiltshire police investigating a sexting scam at Dauntsey's School.

Headteacher Mark Lascelles today confirmed to the Gazette that pupils have been duped into posting explicit images of themselves online in a 'sexting' scam.

Parents at Dauntsey's have been warned that 21 pupils were targeted.

Police are investigating whether boys as young as 13 were offered sex during online exchanges with someone they thought was an older teenage girl.

They were told to send explicit images of themselves via Snapchat, a mobile phone app that allows videos and pictures to be shared. However, it is understood that the 'girl' was in fact male.

Mr Lascelles first wrote to parents back on January 14 after the sexting came to light. He warned them there had been a serious breach of the school's social media protocol and an investigation was underway but on legal advice did not give them full details.

He is writing again today (Monday) by email to apologise that they had to read details they were unaware of in the press. He also seeked to reasure them that everything possible was being done to prevent anything like it happening again.

Staff discovered the scam and immediately alerted police and social services. A 17-year-old boy has been arrested in connection with the incident and released on police bail pending further inquiries.

Mr Lascelles said: "We educate pupils about online risks but there's very little we can do to stop the use of social media such as Snapchat. It is accessed via the 3G or 4G mobile phone networks or from home. It wouldn't be possible through the school's own internet service.

"When we discovered what was happening, we immediately asked the police to investigate and reported the situation ourselves to social services."

A report three months ago on Dauntsey's by the Independent Schools Inspectorate stated: 'The school educates all pupils in e-safety and operates suitable controls and filters regarding the use of the internet.'