An autistic teenager, with a fascination with weapons, made meticulous plans before he left a bomb on a Jubilee line train, the Old Bailey has heard.

Damon Smith, 19, from Rotherhithe, caused panic and alarm at North Greenwich station in October when the train driver realised what they thought was lost property was actually a potentially deadly explosive device.

Although Smith claimed the rucksack was only a prank, investigators found it contain deadly ball-bearing shrapnel triggered by a £2 Tesco clock timer and would have caused carnage passengers.

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Smith, who had moved from Devon to London to start a university computer course, had research his plan in detail.

He printed an al Qaeda article on bomb-making before shredding the paper, jurors were told.

He also allegedly searched the internet for an Islamic State magazine featuring an article about the bomb said to have brought down a Russian airliner in October 2015.

A shopping list for “pressure cooker bomb materials” was also found on an iPad ending in a note to “keep this a secret between me and Allah #InspireTheBelievers”, the court heard.

North Greenwich station

Smith’s Tube journey on the morning of October 20 last year was played in court. Wearing a brown hoodie, he boarded a train from Surrey Quays to Canada Water and joined the Jubilee line and went to Southwark before going back on himself. He alighted at London Bridge, leaving the bomb behind.

There were at least 10 passengers in the carriage and they alerted the driver when they reached Canary Wharf.

The driver took the bag thinking it was lost property and carried on towards North Greenwich until he noticed a wire poking from the clock.

At Smith’s home, police found a blank-firing self-loading pistol, a BB gun, both bought legally, as well as a knuckleduster and a knife which he showed off in an online video.

Smith posed next to an image of the Brussels-born Islamic terrorist alleged to have masterminded the attacks in Paris in November 2015, the court heard.

Smith, now 20, denies possession of an explosive substance with intent, contrary to the Explosive Substances Act 1883 but has admitted the lesser offence of perpetrating a bomb hoax.

The trial continues