(CNN)Notorious hate preacher Anjem Choudary, who led a flag-burning demonstration outside the US embassy on the anniversary of the 9/11 attacks and voiced support for jihad, has been jailed for inviting support for ISIS.
The former lawyer was sentenced to five years and six months in prison. His supporters shouted "Allahu Akhbar" as he was led away from the dock in London's Old Bailey court.
Choudary's co-defendant Mohammad Mizanur Rahman, 33, was also handed a sentence of five years and six months.
Choudary has courted controversy over two decades, skirting the edges of the law, backing extremism but with no proof of actually inciting violence. He earned the wrath of Britain's tabloid newspapers, making him - by his own admission -- the country's "most hated man."
In 2014, he pledged allegiance to ISIS and its leader Abu Bakr al-Baghdadi, bringing him under scrutiny and leading to his arrest.
"Both men were fully aware that Daesh is a proscribed terrorist group responsible for brutal activities and that what they themselves were doing was illegal," said Sue Hemming, head of counter terrorism at the Crown Prosecution Service, using an alternative name for ISIS.
"Those who invite others to support such organizations will be prosecuted and jailed for their crimes," Hemming added.
British authorities say they were able to link Choudary to the battlefields of Iraq and Syria; UK police say they don't know exactly how many of the 850 Britons who have traveled there were directly influenced by him, but they say he is a "key" figure in ISIS's recruitment drive.
"These men have stayed just within the law for many years," Commander Dean Haydon, of the Metropolitan Police's Counter Terrorism Command, said when he was convicted.
"But there is no one within the counter terrorism 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 organizations."
ISIS pledge of allegiance
Despite his vocal support for the terrorist group, Choudary has previously insisted he is not a danger to the public. "I don't pose a threat to anyone in this country," he told CNN in 2014. "I pose an ideological or political threat, definitely."
But authorities in Britain say Choudary has been linked to the radicalization of a string of the terrorists who have stood trial in the UK over the past 15 years.
Radical Cleric on why he hates America 01:09
Together with Omar Bakri Muhammad, he founded the now outlawed radical Islamist organization Al-Muhajiroun. Bakri Muhammad was later banned from the UK over links to al Qaeda.
He was pictured at a protest with Michael Adebolajo, later convicted of the violent murder of British soldier Lee Rigby, and he was linked to Siddhartha Dhar, suspected by authorities of replacing Jihadi John as ISIS executioner.
But rather than traveling to Syria himself, he has stayed in Britain - where he was born and raised -- and taken on the role of a vocal supporter for ISIS and radical Islam.
"Sometimes the propaganda and the verbal jihad is even stronger than the jihad of the sword," he says.
A jury at London's Old Bailey found Choudary (and his associate Mohammad Mizanur Rahman, 33) guilty of "inviting support for a proscribed organization" - a charge he had denied.
Choudary has been repeatedly in the headlines for his views.
Who is Anjem Choudary?
Choudary used to party hard at university -- where, as a young law student, he was known as Andy -- but is now a hard-line Islamist, advocating the introduction of laws based on the teachings of the Quran.
"I believe that the Sharia is the best way of life," he told CNN. "I believe that one day it will come to America and to the rest of the world."
If that comes to pass, he says: "of course, alcohol will be banned, drugs will be banned, pornography will be banned, gambling will be banned."
He is a vocal supporter of jihad
"I preach jihad everywhere in the world but how that manifests itself is different," he told CNN while on bail in December 2015. "From here we can support the Muslims around the world. In other places Muslims are fighting."
In an earlier interview, he claimed: "The best death is one of martyrdom. I would love to die defending myself and my community, but of course death is in the hands of God; our life span will end when he decides."
Inside the mind of radical Islam 08:35
Defending his own decision not to go to Syria, he explained: "My passport has been taken away ... I will continue to struggle, wherever I am."
He thinks the Islamic State is paradise
"There is peace. There's no corruption, there's no bribery, there's no usury, there's no alcohol, gambling -- all of the vices which you're used to in America and other parts of the world don't exist there."
Radical Cleric idealizes Islamic State 01:10
"I believe that Abu Bakr Al Baghdadi -- may Allah protect him -- has brought in the dawn of a new era," he told CNN's Nima Elbagir while on bail awaiting trial in December 2015.
And that "moderate" Islam does not exist
"There is no such thing as a 'radical' or a 'moderate' form of Islam," he insists. "A woman is either pregnant or not pregnant.
"If you abide by Islam, you'll follow what is in the Quran and the traditions of the prophet."
Radical cleric speaks about ISIS 04:37
He believes notorious acts of terrorism are justified
"What took place on 9/11 or 7/7, or on 3/7 in Madrid, I can see they have an Islamic justification," he says.
Choudary insists attackers from al Qaeda and ISIS are following the teachings of Islam - a viewpoint refuted by more moderate clerics.
"The Quran says, 'Whatever the prophet did, do it; whatever the prophet forbade, forbid it ... the prophet himself sent many people to assassinate others," he told CNN in 2015.
Inside the mind of radical Islam 08:35
In the wake of the Charlie Hebdo killings in Paris, he said the cartoonists who died had brought the attack on themselves by "dishonoring" the prophet Mohammed
"I think the cause has an effect; if I need to condemn, I need to condemn the provocation ... I cannot condemn them [the killers] ... they have a juristic opinion which they are following."
He's an unapologetic propagandist for ISIS
"I am very proud and happy to lay the seeds of Islam in the hearts and minds of Muslim youths. There is nothing wrong with that," he insists.
"My love for Allah, his messenger, love for the sharia, love for the khilafah [caliphate], love for even jihad. This is part and parcel of Islam, however much people might demonize it."
Extremist cleric Anjem Choudary convicted 02:20
