A Briton who recruited Islamist extremists online to stage holy war worldwide, including Britain's youngest terrorism convict, was jailed for 12 years on Tuesday.
Aabid Khan, 23, built up a computer "encyclopedia" of extremist material including a file on Britain's royal family, London's Blackfriars Crown Court heard during the trial.
"The material seized from you... is amongst the largest and most extensive ever discovered and thus makes this case one of the most serious of its type to come before the courts," said judge Timothy Pontius.
"It is that material... which was possessed by you for a specific intention, to be used in due course to provide practical assistance in terrorist activity," the judge said.
Khan, a former fast food restaurant worker from Bradford, northern England, was jailed after being convicted on three counts of possessing articles for a purpose connected with terrorism.
His cousin and "right-hand man" Sultan Muhammad, also 23, was jailed for 10 years for possessing similar material and making a record of information likely to be useful in terrorism.
On Monday the court convicted the two men as well as Hammaad Munshi, who was 16 at the time of his arrest. Munshi will be sentenced next month.
The trial heard how the material collected included personal information, including addresses, of Queen Elizabeth II, her husband Prince Philip, and their four children -- Princes Charles, Andrew and Edward and Princess Anne.
"Perhaps most chillingly of all was the vest folder demonstrating in careful, methodical and lethal detail the step-by-step instructions of how to make a suicide bomber's vest or belt packed with ball bearings and explosives.
"During the playing of that 20-minute video the stunned silence in court was a telling reflection of the collective horror felt by such a potent demonstration of terrorist resolve."
Khan's father Sabir reacted angrily to Tuesday's ruling, and had to be ejected from court after accusing the judge of being "anti-Muslim." Outside he was restrained after punching a reporter to the ground when asked his name.