A teenager with a talent for chemistry has been jailed for throwing firebombs on to a motorway because he wanted to kill someone.
Nicholas Elger, 17, who was a boarder at the public school Winchester College, said his only regret was failing to take the life of a motorist.
Sentencing Elger to four and a half years, Judge Keith Cutler said he considered the teenager very intelligent but very dangerous.
Cutler told him: “I consider you are a dangerous offender. There is a significant risk to members of the public of serious harm from you in the future.”
Describing the defendant, the judge added: “He’s very intelligent, possibly the most able chemist the college has produced in recent years.
“He’s a very bright boy and for some reason he takes to burgling the school, blackmailing the headteacher and making incendiary devices and throwing them off motorway bridges.”
Judge Cutler said that Elger had written in a diary in hospital stating he wanted to kill patients and staff by “strangling and jumping on heads” and had also heard a voice telling him to kill his doctor.
Elger was sentenced at Winchester crown court for two arson charges over the two attacks on the M3 in September 2017.
The second incident caused the motorway to be closed at Winchester for 11 hours leading to major delays and causing an estiamted £40m of damage to the economy.
Elger was also sentenced for eight burglary and two blackmail charges against Winchester College and two charges of theft from a supermarket.
The burglary and blackmail offences cost Winchester College £52,000 in stolen items and damage and the defendant twice demanded payment of £10,000 in an online currency for him to stop carrying out further break-ins.
The judge previously lifted the defendant’s right to anonymity given to minors because of the public interest in the serious offences.
Tessa Hingston, prosecuting, said he was caught because of a “schoolboy error” by sending a typed blackmail letter but in a handwritten envelope which enabled staff to recognise his distinctive handwriting.
Hingston said that Elger, who has previously been remanded under psychiatric care, had told medical staff that he intended to kill someone in the motorway arson attacks.
She added he told staff: “I do not regret the incident, I regret not doing them differently and not succeeding in killing.”
Hingston said: “The risk of really serious harm was great; if someone had taken avoiding action and swerved into another vehicle someone could have been killed and that was a realistic possibility.”
Robert Morris, defending, said doctors had ruled out personality disorder or psychotic illness and said his actions had been caused by “immaturity and being upset by his parents’ divorce, leaving his school and support networks”. He said he had been a “kind and gentle” child who was “playing up to a bad boy character he had created for himself”.