Damon Smith jailed for planting failed Tube bomb
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.
He said the student's actions came at a time of heightened fear of terrorism, "an all too timely reminder of which were the events in Manchester".
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.
Commander Dean Haydon, head of the Met's Counter Terrorism Command, said Monday's attack at Manchester Arena had demonstrated "the horrifying impact a bomb can have".
"The bomb Smith made was a viable device, but it failed to detonate, which was our good fortune," he said.
Analysis by Daniel De Simone, BBC Home Affairs
Smith grew up in Devon and only moved to London to attend university three months before leaving his homemade bomb on the Tube.
An only child who lived with his mother from a young age, he has a form of autism that impairs social communications but not his intelligence.
An able student, Smith also displayed a persistent fascination with Islamic terrorism and mass murders.
Friends were shown violent propaganda by so-called Islamic State and Smith created YouTube videos of himself using computer games to re-enact infamous real-life mass killings.
In a shopping list of the components for his bomb, he had written: "And keep this a secret between me and Allah #InspireTheBelievers."
He tried to cover his tracks by shredding the manual and deleting the list from an iPad, but detectives were able to recover them.
Dismissing Smith's claim that the device was a "prank" smoke bomb, explosives experts say it was viable and would have caused mass casualties had it been constructed slightly differently.