A teenager has been jailed after making bogus bomb threats to hundreds of UK schools and sparking an airport security scare.

George Duke-Cohan twice targeted schools in the UK and US with hoax messages that triggered evacuations, before phoning in a fake report of a hijacked aircraft while under investigation.

The 19-year-old, from Watford, Hertfordshire, emailed Marlborough College in Wiltshire and referred to the Columbine high school shooting.

He was jailed on Friday for three years by Judge Richard Foster at Luton crown court.

The recorder of Luton told him: “You knew exactly what you were doing and why you were doing it, and you knew full well the havoc that would follow. You were playing a cat-and-mouse game with the authorities.

“You were playing a game for your own perverted sense of fun in full knowledge of the consequences.”

In his sentencing remarks, the judge added: “The scale of what you did was enormous. Schools were evacuated and, where they were not, those in charge had to take agonising decisions.

“The passengers and crew on that flight on 9th August must have been terrified when their plane was taken to a quarantined area, and, apart from the financial cost, the onward travelling plans and connecting flights would have been in disarray.”

Duke-Cohan pleaded guilty in September to three counts of making hoax bomb threats.

The teenager, who was doing an IT course, first created panic in March 2018 when he emailed thousands of schools in the UK warning about an explosive. The National Crime Agency said more than 400 schools were evacuated as a result.

Rebecca Austin, prosecuting, said he had sent emails to more than 1,700 schools in the UK between 16 and 19 March this year. They succeeded in causing “alarm and anxiety”, and one email issued threats and demanded $5,000 be sent to a website.

Police arrested Duke-Cohan days later, but he was able to send another batch of emails to schools in the US and UK while under investigation in April.

The court heard that Marlborough College was targeted on April 13 by what was referred to as the “Apophis Squad” hoax emails. Austin said it was “clear” that Duke-Cohan used the influence of the Columbine attack of 1999 to add “authenticity”.

The email sent to Marlborough College said: “We follow in the footsteps of our two heroes who died in the Columbine high school shooting.”

Duke-Cohan was arrested for a second time and released on pre-charge bail with conditions that he did not use electronic devices. Before long his name was in the frame for a third hoax, regarding a bogus tip-off that hijackers had taken over a United Airlines flight from Heathrow to San Francisco.

Detectives found that Duke-Cohan had made the calls to San Francisco Airport and its police force while he was on pre-charge bail for the two previous offences.

Speaking to an operator, he identified himself as “Mike Sanchez” and said his daughter had called him in a “distressed state” from the plane. A tweet sent after the plane landed included the words “9/11 remake”.

He was arrested for a third time at his home in Watford on 31 August this year.

The teenager was sentenced to one year for the emails sent to schools and two years for the airport security scare. The judge said that, for the purposes of sentencing, he accepted that Duke-Cohan has autism spectrum disorder.