Judge Charles Haddon-Cave said Ahmed Hassan had constructed a homemade bomb "to kill as many members of the British public as possible".

Hassan left the improvised bucket bomb filled with screwdrivers, knives, nuts, bolts and "Mother of Satan" TATP explosives in a carriage carrying 93 passengers on September 15 last year.

It partially exploded at Parsons Green Tube station in west London, one stop after he had alighted, triggering a stampede that injured tens of other passengers.

The judge in the London court called Hassan a "dangerous and devious individual" who had let down the country that gave him shelter, the foster charity that cared for him and the college he attended.

Hassan had benefited from "every kindness" since arriving in Britain in October 2015, yet was consumed with "dark thoughts" against Britain.

"One can only imagine the sense of betrayal felt by all those at Barnardo's and Brooklands College whom you duped," said Haddon-Cave.

The judge said he believed Hassan had trained with the Islamic State jihadist group in Iraq, and that he may be older than 18.

Hassan told jurors that he did not intend to hurt people, and that he was "bored and stressed" and wanted to start a fire.