Britain's most infamous defender of Islamist extremism was found guilty of eliciting support for Isis (Islamic State), marking what authorities described as a milestone in the British campaign to combat homegrown terrorism.
The verdict against Anjem Choudary, 49, is the first major conviction against a man seen across Europe as a Pied Piper for young radicals and a cheerleader for Isis.
His conviction immediately became the most significant example of how Britain and other European nations are moving to expand their counterterrorism operations, targeting not just active cells but also the voices of incitement.
A top associate of Choudary - Mohammed Rahman, 33 - was also convicted, and both now face up to 10 years of jail time. The verdict came after years in which both men had mostly dodged British justice, doing so by successfully playing the same democratic system they often railed against.
Choudary, for instance, is a trained lawyer, and he often maintained that his polemic statements - such as calling for strict Islamic law in Britain and turning Buckingham Palace into a mosque - were expressions of free speech designed to "bait" the British press. His conviction, however, came after he appeared to cross a line by openly supporting Isis.
In lectures and statements posted on social media and YouTube, he encouraged youths to embrace Isis and denied its documented war atrocities, prosecutors said. In one piece of vital evidence, officials said, he pledged allegiance to Isis' leader in a conversation with a terrorism suspect.
"These two men knowingly sought to legitimise a terrorist organisation and encouraged others to support it," Sue Hemming, head of counterterrorism for the Crown Prosecution Service, said. "They used the power of social media to attempt to influence those who are susceptible to these types of messages, which might include the young or vulnerable."
The men were convicted on June 28, but the verdict was announced today, after the conclusion of a related trial. They are set for sentencing on September 7.
Counterterrorism officials and experts have long described Choudary - a soft-spoken lawyer with a salt-and-pepper beard known for wearing traditional Muslim robes - as a leading figure in the dark networks across Europe that have fostered homegrown extremism and encouraged young Muslims to fight in the Middle East.
"These men have stayed just within the law for many years, but there is no one within the counterterrorism world that has any doubts of the influence that they have had, the hate they have spread and the people that they have encouraged to join terrorist organisations," Dean Haydon, head of the Metropolitan Police's Counter Terrorism Command.
These two men knowingly sought to legitimise a terrorist organisation and encouraged others to support it
During the investigation, Haydon said, 20 years' worth of material was considered. They included information recovered from 333 electronic devices containing 12.1 terabytes of storage data. In a meeting in a restaurant in July 2014. Choudary and Rahman, officials said, had contacted Mohammed Fachry, a convicted terrorist in Indonesia, and pledged their allegiance to Isis leader, Abu Bakr al-Baghdadi.
Via social and traditional media, Choudary has openly defended known terrorists and called for the spread of Islamic law. His comments often harboured an air of the grandiose, leaving some wondering whether he was a publicity hound more than anything else.
"We believe there will be complete domination of the world by Islam," he told the Washington Post in 2014. "That may sound like some kind of James Bond movie - you know, Dr No and world domination and all that. But we believe it."
But over the past 15 years, counterterrorism experts say, the majority of Britons convicted of offenses related to Islamic extremism have been members or supporters of his shadowy organisations. They included the two men charged with slaughtering Lee Rigby, a British Army soldier killed on the streets of London in May 2013.
Yet other than a minor charge for holding an illegal demonstration, a series of allegations against Choudary never really stuck.
In September, 2014, however, exasperated British authorities arrested Choudary and Rahman after mounting their most rigorous case against him. A detailed report compiled on Choudary by Hate Not Hope, a British anti-extremist organisation, portrays Choudary as a sinister but savvy figure with deep connections to extremism. Well over 100 Britons with some connection to Choudary and his al-Muhajiroun network have gone to Syria to fight, the group said.
Choudary has disputed that he ever coaxed jihadists to go and fight. But he routinely painted Isis as a religious utopia.
"If you look now in the area controlled by the Islamic State, the Jews, the Muslims and the Christians are living side by side in security," he once told the Guardian. "It's not true that people are being slaughtered. Those people who are allied with the previous regime or those who are fighting against the Muslims, certainly they will be fought against."
Choudary also maintained early and long ties with a host of other radical groups across Europe, including Sharia4Belgium. That group is now labelled a terrorist organisation in Belgium, and authorities see it as an incubator of homegrown terror and young jihadists who have joined Isis.
"It seems incredulous that he was allowed to continue all these years," said Nick Lowles, executive director of Hope Not Hate. "This really does put an end to his organisation. Others will try to step into his place. But the people who come after him won't have the same credibility or media profile."