A student who made a bomb filled with ball bearings and left it on a Tube train has been jailed for 15 years.
Damon Smith put his homemade device into a rucksack and left it on a Jubilee line train in October 2016.
The 20 year old claimed it was a prank but was found guilty of possession of an explosive substance with intent.
Sentencing, the Old Bailey judge told Smith “the seriousness of what you did cannot be overstated”.
The court heard had the device exploded, it would have gone off as commuters left the North Greenwich station platform.
Smith, who has an autistic spectrum disorder, built the device using a £2 clock from Tesco and an al-Qaeda online article on bomb-making.
Before sentencing, his lawyer had pleaded with the judge for “mercy” and said the “unique” student had “learned his lesson”.
But Judge Richard Marks QC said that while Smith was not motivated by terrorism, he was a dangerous offender who had constructed other devices before planting one on the Tube.
“I am influenced by your history of preoccupation with weapons and bombs as well as by your condition which makes it difficult for you… to understand and fully appreciate the very serious potential consequences of your actions,” he said.
His mother, who he lived with in Rotherhithe, south-east London, said her son was “just a vulnerable little boy who needs help, not prison”.
“He just made a smoke bomb and the prank went wrong, and now he’s paying for it,” she said.
The former altar boy smiled in the dock as he was sentenced to 15 years in a young offenders’ institution with an extended period of five years on licence.