A London court convicted three men on anti-terrorism charges on Monday, including a teenager who becomes the youngest Briton found of guilty of such offences.
Hammaad Munshi, the grandson of a leading Islamic scholar, was 16 when he was arrested in a police crackdown on an extremist cell for which he was described as the computer expert.
Blackfriars Crown Court in London found him guilty of distributing detailed instructions online on how to make napalm, explosives, detonators and grenades. He was convicted of making a record of information, but not possessing it.
"When looking at the evidence against Hammaad Munshi I was satisfied there was enough for a case to go to court and that it was in the public interest, despite his young age," said Karen Jones of the Crown Prosecution Service.
"Let there be no doubt, these are dangerous individuals," added John Parkinson, head of the police counter-terrorism unit in nearby Leeds, northern England.
Munshi is now 18. The court found Aabid Khan, 23, a "key player" in radicalising impressionable youths by inciting them to "violent jihad", recruited him at the age of 15. The third defendant convicted was Sultan Muhammad, 23.
Between 2005 and 2006 the pair had online exchanges about "black powder explosives," and on one occasion discussed how the schoolboy could smuggle a sword through airport security.
"The prosecution told the jury of his dedication to the cause of Al-Qaeda, and of discussions with Aabid Khan which included how he could travel abroad and smuggle a sword with him," Jones added in a statement.
An 11-person jury convicted the defendants of eight offences under the Terrorism Act between November 2005 and June 20, 2006.
Munshi's grandfather is Sheikh Yakub Munshi, head of the Islamic Research Institute of Great Britain at the Markazi Mosque in Dewsbury, near Leeds, which was home to suicide bombers who killed 52 people in London in 2005.