A British student, who left a homemade bomb packed with ball bearings and shrapnel on a London underground train on its way to the Canary Wharf financial district last October, was jailed for 15 years on Friday.

Damon Smith, 20, set the timer and left the train but the bomb failed to explode and was later reported by passengers. It was made safe by police at North Greenwich station on the Jubilee line, one stop away from Canary Wharf.

During a search of his home, police found a blank firing pistol, a knife and a knuckleduster while on social media he had "liked" a number of videos relating to explosions.

A forensic scientist was also able to reconstruct a shredded document to reveal it was pages from an al Qaeda-published magazine that gave instructions on bomb-making. A list of materials needed for making a bomb were found on his iPad and components needed to make a device were discovered at his home.

Smith claimed the device was just a smoke bomb and that whole incident had been a prank but was convicted at London's Old Bailey court earlier this month of planning to cause an explosion.

"We have seen this week the horrifying impact a bomb can have. And whilst there is no connection between Manchester and Greenwich it brings into stark reality just how devastating it could have been," Commander Dean Haydon said.

"The bomb Smith made was a viable device, but it failed to detonate, which was our good fortune."