LONDON — A British teenager has been jailed for three years after his bogus bomb threats led to school evacuations and an airport security incident.

George Duke-Cohan, 19, touched off panic in March 2018 when he emailed thousands of schools, warning about an explosive. The National Crime Agency says more than 400 schools were evacuated.

He later caused a scare by telephoning San Francisco Airport and claiming his daughter had contacted him while on a United Airlines flight from Heathrow to say her plane had been hijacked.

Judge Richard Foster told Duke-Cohan on Friday that the passengers on the Aug. 9 flight "must have been terrified when their plane was taken to a quarantined area."

Fosters says Duke-Cohan was "playing a game" for his "own perverted sense of fun."