A 14-year-old pupil has been arrested after a head was told to pay £30,000 or one of her teachers would be killed.

Police said the boy, from Witton Park school, Buncer Lane, Blackburn, was quizzed on suspicion of blackmail.

Detectives questioned the child over an email, sent to school head teacher Gwen Onyon at 10pm last Thursday, which made the threat.

Police said the email also made claims about a bomb in the school grounds.

The message was discovered by staff on Friday morning. They contacted police who quickly established there was no danger to them or pupils. The school opened as normal.

Detectives later arrested the boy on suspicion of blackmail at his home in Blackburn, police said.

A police spokesperson said: “On Friday January 15, we were asked to investigate the contents of an email which had been sent to the headteacher at Witton Park High School.

“As a result of inquiries, a 14-year-old boy was arrested on Friday afternoon and bailed pending further inquiries.”

Mrs Onyon said: "Witton Park High School received an anonymous email which was reported to the police. After being reassured by police that it was safe to remain open, the school day continued as normal.

“The school cannot comment any further while an investigation is underway."

The school refused to say whether the pupil had been suspended.

But Simon Jones, Blackburn with Darwen National Union of Teachers secretary and executive member, said: “In circumstances such as these it would be normal to suspend a pupil at least while investigations take place.

“This incident is not unheard of and is part of cyberbullying.

"I am aware of situations where pupils have got hold of teachers' phone numbers and emails and have sent them messages.”

The teenager has been bailed until March while investigations continue.