Radical cleric Anjem Choudary is facing jail after being convicted of supporting Islamic State (IS).
The 49-year-old, who has been branded one of the most dangerous hate preachers in the UK, also encouraged support for the terrorist group in a series of talks posted on YouTube, the Old Bailey heard.
He was found guilty on 28 July but due to reporting restrictions his case can only now be reported.
He now faces up to 10 years in jail for inviting support for a proscribed organisation when he is sentenced on 6 September.
Choudary has for decades avoided arrest despite being a leading figure in the banned extremist group al-Muhajiroun (ALM) and his supporters going on to be convicted of terrorism.
This includes one of Lee Rigby's killers, Michael Adebolajo, the suspected IS executioner Siddhartha Dhar and ALM's former leader Omar Bakri Muhammad, who fled the UK after the 7 July 2005 London bombings.
Choudary and co-defendant Mohammed Mizanur Rahman, 33, were found guilty of inviting support for IS between June 29 2014 and March 6 2015.
The court heard how the pair were arrested in September 2014 after telling their supporters to obey Isis leader Abu Bakr al-Baghdadi and travel to Syria to support the "caliphate".
They also invited others to support IS through speeches and made a public oath of allegiance to its leader.
It came after Dhar urged Choudary to swear an oath of allegiance to al-Baghdadi, tweeting: "U should tweet...I think a lot of muslims are excited. The Islamic verdict would be good from u." He added that his support for IS would be "gold on Twitter".
Choudary and Rahman both subsequently declared their support for IS on the ninth anniversary of the 7 July 2015 bombings, in 2014, in an "oath of allegiance".
Prosecutor Richard Whittam QC argued: "Terrorist organisations thrive and grow because people support them and that is what this case is about. Do not confuse that with the right of people to follow the religion of their choice or to proclaim support for a caliphate."
Between August and September 2014, Choudary and Rahman posted speeches on YouTube encouraging support for Isis.
In one speech titled: How Muslims Assess the Legitimacy of the Caliphate, Choudary said: "I would just say, uh you know, for people who want to live under sharia law, obviously this is a great thing, and for those people who say we are promoting Isis, they are not even called Isis any more. Rather, you have an Islamic state where you have millions of people who are governed by the sharia law and I don't think it is against the law to go and live there and want to abide by sharia law."
Choudary also took to social media to express support for Isis, the court heard.
The father-of-five denied encouraging his followers to back the terror group and insisted the oath had been made without his knowledge. He said of the pledge: "It is completely unnecessary. For the rest of the Muslims it is obedience from the heart."
He, however, continued to express extreme views during his trial and even refused to denounce the execution of journalist James Foley by so-called Jihadi John in Syria in 2014. Counterterrorism chiefs say they have spent almost 20 years trying to bring Choudary to court.
He attracted controversy with his views on implementing Sharia law in the UK – which included turning Buckingham Palace into a mosque – while building up a strong following on social media.
Commander Dean Haydon, Head of the Met Police's Counter Terrorism Command, said: "Over and over again we have seen people on trial for the most serious offences who have attended lectures or speeches given by these men.
"The oath of allegiance was a turning point for the police – at last we had the evidence that they had stepped over the line and we could prove they supported Isis.
"This has been a significant prosecution in our fight against terrorism and we will now be working with communities to ensure that they are not replaced by others spreading hate."
More to follow...