Anjem Choudary, one of the UK's most recognised radical Islamist preachers, will be sentenced on Tuesday after being found guilty of directing a banned organisation and encouraging support for it online.
Long in the authorities' sights, the 57-year-old former lawyer has already spent time in jail for supporting the jihadist Islamic State group.
But he could now spend the rest of his life behind bars following a joint investigation by the UK, the United States and Canada.
A jury at Woolwich Crown Court in southeast London last week convicted him of being the "caretaker" leader of Al-Muhajiroun (ALM), which was proscribed in the UK in 2010.
The group was founded in 1996 by north London-based Syrian-born cleric Omar Bakri Muhammad with the goal of establishing an Islamic caliphate in the UK.
Its members have been implicated in a number of attacks, including the murder of British soldier Lee Rigby in 2013, and attacks on London Bridge in 2017 and 2019.
Despite claims it had been disbanded, prosecutors said Al-Muhajiroun continues to exist under different names, including the New York-based Islamic Thinkers Society.
US law enforcement officers infiltrated the group and attended online lectures it hosted with Choudary in 2022 and 2023, sparking police probes in Britain and Canada.
"There are individuals that have conducted terrorist attacks or travelled for terrorist purposes as a result of Anjem Choudary's radicalising impact upon them," Dominic Murphy, of London's Metropolitan Police, said after his conviction.
Rebecca Weiner, deputy commissioner of the New York Police Department, told reporters Choudary's conviction was "historic" and described him as a "shameless, prolific radicaliser".
"It is usually the foot soldiers, the individuals who are brought into the network who go on to commit the attacks who are brought to justice," she said.
"It's rarely the leader, which is what makes this a particularly important moment."
Choudary, the son of a market trader, became a familiar figure in the media after staging demonstrations in front of UK mosques, embassies and police stations in the early 2000s.
His ultimate goal, he said, was to fly the flag of Islam above 10 Downing Street, the prime minister's residence.
He was jailed for five and a half years in 2016 for encouraging support for the Islamic State group, and was released early from prison in 2018.
Choudary's co-defendant Khaled Hussein, 29, from Edmonton, Canada, was also convicted of membership of ALM and will be sentenced on Tuesday.
