The extremist preacher Anjem Choudary has been found guilty of directing a terrorist organisation.

Choudary, one of the most important radicalisers in the UK, was caught in an international undercover investigation into his long-banned organisation.

Officers in the US and Canada posed as would-be terrorists to attend online lectures as British investigators bugged Choudary’s home.

Conviction for directing the banned al-Muhajiroun (ALM) group means Choudary could be jailed for life – but also reveals his enduring determination to recruit followers.

Along with Choudary, one of his followers, Canadian Khaled Hussein, 29, was convicted of being a member of the banned group.

For more than a quarter of a century Anjem Choudary, 57, has promoted the Islamist ideology underpinning jihadist violence in the UK.

In the late 1990s, the former solicitor was a student of Omar Bakri Muhammad, a Syrian-born firebrand cleric who formed ALM.

Choudary became the group’s second-in-command – but by 2010 the British government had banned the group and off-shoots because of its members’ links to terrorism attacks.

When Barki Muhammad was jailed in Lebanon in 2014, Choudary’s trial heard that he took on “the caretaker role” of running the organisation and had continued to spread “a warped and twisted view of religion”.

That takeover occurred as the self-styled Islamic State group stormed over Syria and Iraq – and Choudary was jailed two years later for inviting his acolytes to support the group.

He was released on licence from HMP Belmarsh in 2018 – with the conditions of his sentence, including a ban on speaking in public, ending in 2021.

Choudary was accused of holding the leadership of ALM from 2014 until possibly as late as July 2023 – but the charges from this second trial concern events after the terms of his sentence ended in 2021.

Tom Little KC, prosecuting, told Woolwich Crown Court that after Choudary was free, he began delivering ideological lectures to supporters in New York who called themselves the “Islamic Thinkers Society”.

Mr Little said that ITS was the same organisation as ALM and the meetings had been infiltrated by undercover officers.

One supporter was Canadian petrol station attendant Khaled Hussein, 29, who called himself Abu Aisha al Kanadi.

He helped Choudary administer online meetings, and was already being watched by investigators in the Royal Canadian Mounted Police.

By June 2021 the RCMP and the NYPD were sharing intelligence. Within months the Metropolitan Police had teamed up with them as Choudary and Hussein became bolder.

The pair were working on “Twitter storms” in which they posted prolifically on social media sites, campaigning for the release of Islamist prisoners.

Choudary was careful not to personally advocate violence – and Hussein also tried to cover his public tracks. But neither man knew that they were giving away evidence to the US and Canadian undercover officers who were attending ITS talks

“The Islamic Thinkers’ Society are actually al-Muhajiroun North America,” Hussein told one of the officers.

Last July, Khaled Hussein travelled to the UK and was arrested at Heathrow airport.

Woolwich Crown Court heard he told detectives that he was studying English literature and wanted to visit Shakespeare’s birthplace.

But they knew he was really coming to meet Choudary, a man he idolised. Hussein had unwittingly told one undercover officer that “most people don’t know I’m part of al-Muhajiroun” – and the investigators also had Choudary’s side of communications.

Choudary had advised Hussein on tourist sites to visit, and told him: “You are also not too far from Woolwich – the famous Lee Rigby issue.”

That was a reference to the 2013 murder of Lee Rigby, a soldier killed by two of ALM’s supporters, just a few miles from the south London court where Choudary has now been convicted.

British investigators had also listened in to Choudary’s conversations with his wife in their east London home.

She was concerned about his online lectures to America – but Choudary insisted: “I don’t say anything dodgy.”

When she warned he was talking to people he might not personally know, he replied that he wanted to encourage them.

Her concerns were valid. At times Choudary was lecturing just five people – and two of them were undercover officers.

Over the years, al-Muhajiroun operated under a number of different names. Eleven of its offshoots were proscribed by successive home secretaries. Keeping track was like “chasing marbles down the stairs” the court was told.

Amid all the name-changes, one figure was constant – and Choudary’s second conviction reveals the challenges for police in dealing with a committed extremist.

“When he was released from prison, and became free from his licence conditions in 2021, we didn’t stop investigating,” said Commander Dominic Murphy, head of Counter Terrorism Command at the Metropolitan Police.

“Clearly [he] can continue to have an influence way beyond the shores. We now need to be mindful about who might come behind Anjem Choudary.”

All such investigations, which also involve MI5, must balance the benefit of quickly arresting and charging members of a network, with allowing more time to snare leaders and uncover more deeply hidden plans.

A senior British security official said: “Putting a stop to ALM radicalisation has been a key objective of the counter-terrorism community for some years – and this verdict builds on a range of actions that made it difficult for ALM to operate.

“This investigation is a great example of domestic and international partners tackling terrorism – an approach that is vital when disrupting today’s online and internationally connected threat.”

Deputy Commissioner Rebecca Weiner of the New York Police Department said the investigation had disrupted the “the radicaliser himself”, rather than the foot soldiers who are caught up in the attacks. Officers in the city had spent 20 years monitoring ITS because it had been an “extremist incubator”.

“This case represents in many ways, the borderless nature of the threat,” said Dept Comm Weiner.

“It spans agencies, it spans countries, it spans an ocean. ALM has had a big footprint in the UK… but in New York City, we’ve seen a number of individuals who have been arrested, convicted on terrorism charges for involvement with ITS-ALM branch in New York. And having that footprint means that collectively we work together and we spend significant resources to address public safety.”

In the witness box, Choudary downplayed his significance. He complained he was like a top footballer remembered for just one part of their career.

“If you ask about Kevin Keegan, people say he plays football for Liverpool,” Choudary told the court. “People look at me and think al-Muhajiroun.”

But the prosecution showed jurors that ALM had not disappeared in a puff of smoke – and Choudary had boasted in online talks in 2022 of his battle with the authorities.

“Even in this country my dear brothers it has become very difficult,” he told followers. “After so many people went abroad, so many people become Shaheed [martyred], many people have been arrested…

“When I went to prison … they opened up a separation centre for me and my dear brothers because they had become so worried about our Da’Wa [promotion of beliefs].

“They said to me … you are the number one radicaliser in Britain… that is a badge of honour for me.”

In another recording, Choudary performed a technical soundcheck before an interview with CNN in which he said “1, 2, 3, 4, 5…..9/11, 7/7, 3/11.”

Those last three were references to the attacks in New York on the 11th of September 2001, in London on the 7th of July 2005 and in Madrid on the 11th of March 2004.

But ultimately, Choudary was under investigatory pressure – and knew it.

The day after his mentor Omar Bakri Muhammad was released from prison in Lebanon in March 2023, Choudary asked him for advice.

He moaned that the UK was a “complete disaster”. Attracting recruits had become “almost impossible”.

“Every channel I make on Telegram, they ban it. Anything I do, Sheikh, they ban it. Honestly I’m the most banned person.”

They reminisced about their “best brothers” who had been killed in Syria or Iraq.

Choudary’s fate on the other hand is to go back to a prison cell. He and Khalid Hussein will be sentenced on 30 July.

Additional reporting by Steve Swann, senior home affairs producer.