A weapons-obsessed student is facing years behind bars for planting a home-made bomb on a busy Tube train.
Former altar boy Damon Smith built the device at home with a £2 clock from Tesco after googling an al Qaida article entitled Make A Bomb In The Kitchen Of Your Mom.
A jury at the Old Bailey took two hours to find Smith, 20, guilty of possession of an explosive substance with intent.
He had already admitted the lesser offence of making a bomb hoax.
Smith, who smiled throughout his trial, made no reaction in the dock as the verdict was given.
On the morning of October 20 last year, Smith, then aged 19, packed a rucksack with explosives and deadly ball-bearing shrapnel as he headed off to college in Holloway, north London.
He was caught on CCTV as he travelled on the Jubilee Line, casually flicking through a text book before getting off and leaving the bomb on the floor, timed to go off within minutes.
At least 10 passengers were in the carriage at the time and some of them spotted the abandoned rucksack and alerted the driver.
But the driver at first dismissed it as lost property and took it into his cab and carried on towards North Greenwich, jurors were told.
During the journey he spotted wires coming out and he raised the alarm as he pulled into the station.
Had Smith's bomb worked, it would have exploded just as commuters were being ordered off the platform, the jury heard.
The defendant went on to college and, on returning home in the evening, checked the internet for news of what he had done.
Upon his arrest by counter-terrorism officers, Smith admitted making the bomb but claimed he only meant it to spew harmless smoke as a Halloween joke.
He told police he had been inspired from watching someone on a YouTube channel called Trollstation doing a bomb prank.
A search of Smith's home in Rotherhithe, south London, revealed his fixation with guns, explosives and other weapons.
Police seized a blank-firing self-loading pistol and a BB gun, both bought legally, as well as a knuckleduster and a knife which he showed off in an online video.
Smith watched YouTube videos on explosions and posted a picture of himself on Facebook in a Guy Fawkes mask holding handcuffs and a knuckleduster.
Police also uncovered torn-off scraps of shredded paper with bomb-making instructions on it and a "shopping list" of components.
Smith told police he was interested in Islam but denied being an extremist even though he posed next to an image of the Brussels-born Islamic terrorist alleged to have masterminded the attacks in Paris in November 2015
In his defence, extracts of a psychiatric report were read out confirming an autism spectrum disorder.
He had been interested in bomb-making since the age of 10 and said that it was "something to do when he was bored".
Smith, who grew up living with his mother in Newton Abbot, Devon, said he had thought about putting a bomb in a park but decided it would be "more funny" to delay train passengers.
His lawyer, Richard Carey-Hughes QC, told jurors that Smith was no "hate-filled jihadi", saying he intended to "make something that looked like a bomb but not function as one".
Judge Richard Marks QC adjourned sentencing until May 26 to allow time for a probation report on Smith's risk to the public and further psychiatric reports.
Sue Hemming, of the CPS, said: "Damon Smith's actions were incredibly dangerous and the consequences had the device worked do not bear thinking about."
Commander Dean Haydon, the head of the Met's Counter Terrorism Command, said: "Throughout this investigation and subsequent trial, Smith claimed that his actions were meant as a harmless prank and that the object was nothing more than a smoke bomb.
"It is hard to believe that leaving what has been described as an improvised explosive device on a Tube train, on a weekday morning, can be construed as anything but an attempt to endanger life.
"It is fortunate that the device failed to work and that no one was injured.
"At a time when the threat level remains at severe, I find it unlikely that anyone would consider his defence as an appropriate excuse for his actions.
"The jury rightly disagreed with him and I expect that Smith will now face a significant prison sentence."