The teenager who planted the Parsons Green Tube bomb which injured 51 passengers will be sentenced later.
He made a bomb with 400g of “Mother of Satan” explosives and 2.2kg of shrapnel while his unsuspecting foster parents were on holiday in Blackpool.
The photography student, who claimed to aspire to be the new David Attenborough, will be sentenced for attempted murder by Mr Justice Haddon-Cave later.
The court had heard he was referred by Barnardo’s and Surrey social services to Prevent but kept his murderous plans a secret.
On the morning of September 15 last year, Hassan left his home and caught a train to Wimbledon carrying his bomb inside a Lidl bag.
Twenty-three passengers suffered burns, with some describing their hair catching fire and their clothes melting in the blast.
Meanwhile, Hassan destroyed his phone and changed into a Chelsea shirt as he fled London with more than £2,000 in cash but was picked up by police at the Port of Dover the next day.
Hassan’s foster parents Penny and Ron Jones, who were awarded an MBE in 2010, did not give evidence in the trial.
Afterwards they said authorities should have warned them to look out for signs of radicalisation.
Mrs Jones told ITV News: “I am cross with him for what he’s done, and that he’s done this in my house makes me feel very, very betrayed, I can’t help that. Because he’s such a bright and intelligent child, he’d got a good future ahead of him.”
Commander Dean Haydon, head of Scotland Yard’s Counter Terrorism Command, said he was “intelligent and articulate” but also “devious and cunning in equal measures”.
He said: “On the one hand he was appearing to engage with the (Prevent) programme but he kept secret what he was planning and plotting.”
Mr Haydon said it was “good fortune” the bomb did not fully detonate and kill and injure many passengers.
A review of Hassan’s dealings with Prevent is under way.