A teenager has admitted making hoax bomb threats to thousands of schools, including seven in Hertfordshire and four in Bedfordshire.

A teenager has admitted making bomb threats to thousands of schools, including seven in Hertfordshire and four in Bedfordshire.

George Duke-Cohan appeared at Luton Magistrates’ Court yesterday and pleaded guilty to three counts of making hoax bomb threats, which included one to a United Airlines flight travelling from the UK to San Francisco last month.

The 19-year-old from Watford was first arrested days after sending bomb threats which resulted in more than 400 schools being evacuated in March this year.

The mass email threat was sent to schools up and down the country, including in The Valley School in Stevenage, St Albans High School for Girls and Samuel Ryder Academy in St Albans.

In Bedfordshire, Sandy Upper School, Fairfield Park Lower in Fairfield, Roecroft School and Pippin Pre-School in Stotfold all evacuated after receiving the threat.While under investigation in April, Duke-Cohan sent a mass email to schools in the UK and the US claiming that pipe bombs had been planted on the premises.

National Crime Agency investigators working with the FBI identified that while on pre-charge bail for the threats to schools, Duke-Cohan made further bomb threats to the US-bound flight via phone calls to San Francisco Airport and their Bureau police.

In a recording of one of the phone calls which was made while the plane was in the air, he posed as a worried father and claimed his daughter contacted him from the flight to say it had been hijacked by gunmen, one of whom had a bomb.

NCA senior investigating officer Marc Horsfall said: “George Duke-Cohan made a series of bomb threats that caused serious worry and inconvenience to thousands of people, not least an international airline.

“He carried out these threats hidden behind a computer screen for his own enjoyment, with no consideration for the effect he was having on others.

“Despite being arrested and having conditions imposed restricting his use of technology, he persistently broke those conditions to continue his wave of violent threats.

“This investigation proves that operating online does not offer offenders anonymity. We will identify you and you will be brought before the courts.”

Duke-Cohan was arrested by NCA officers for the third time in Watford on Friday.

He has been remanded in custody and is due to appear at Luton Crown Court on September 21.