A senior judge hailed the "extraordinary" investigation which brought an Islamic State terrorist to justice for a plot to kill the Prime Minister Theresa May.
Naa'imur Zakariyah Rahman, 20, could be facing life behind bars for planning to bomb the gates of 10 Downing Street, kill guards and then attack Theresa May with a knife or gun.
He had pledged allegiance to IS and collected what he thought was an explosives-packed jacket and rucksack when he was arrested last November.
The drifter, originally from Birmingham, thought he was being helped by an IS handler when in fact he was talking to undercover officers.
Following an Old Bailey trial, Rahman, from Finchley, north London, was found guilty of preparing acts of terrorism in Britain.
Midway through the trial, he admitted helping his friend Mohammed Aqib Imran to join IS in Libya by recording an IS sponsorship video.
Trial judge Mr Justice Haddon-Cave said the evidence against Rahman was "overwhelming" as he adjourned sentencing to August 31.
He said: "Mr Rahman, you have been found guilty of these serious charges by this intelligent and hard-working jury who has seen through your web of lies."
The defendant mumbled "thank you" before being led from the dock.
The senior judge also paid tribute to the way the "extraordinary" case had been "robustly investigated, prepared and presented".
He added that it would be "extremely reassuring for the public as to how this remarkable investigation has been conducted".
Rahman was snared by a network of undercover counter-terrorism officers from the Metropolitan Police, the FBI and MI5.