Radical cleric Anjem Choudary has been arrested in a series of dawn raids along with eight other men on suspicion of supporting a banned terrorist group.
The men, who were all seized in London, were arrested on suspicion of being members of, or supporting, extremist organisation al-Muhajiroun, as well as encouraging terrorism.
Lawyer-turned-preacher Choudary was detained shortly after firing out a series of anti-Western messages at 5am on social-networking site Twitter, including claims that the definition of terrorism is “more suitable for the US/UK policy in Muslim lands”.
A resident who lives near a terraced house where Choudary was believed to have lived in Walthamstow, east London, said the preacher and his family recently moved out but there had been police activity at the property the weekend after he left.
And Derek Rayner, a retired painter and decorator who has lived on the street for 50 years, said of Choudary: “I was very much aware he was living in the street.
“I didn’t know much about him, other than what I read in the papers.
“He kept himself to himself. It was noticeable that there were comings and goings. Sometimes you wouldn’t see him for a couple of weeks. Then when he was back, you would see him walking up and down the road.”
He said he stopped speaking to Choudary following comments he reportedly made about murdered soldier Lee Rigby and Islamic State militants.
“I used to speak to him to just say ‘good morning’ but having seen the things that he had been saying... I won’t give him the time of day now.”
He said he had not seen the cleric for around a week.
“I wasn’t totally sure he had moved out - I thought he might have just moved out while they were doing the house up. They have totally gutted the house.
“I have seen him moving stuff out. I wasn’t sure if it was going to be permanent or just temporary.”
Counter-terrorism police are searching 18 addresses across London, and one in Stoke-on-Trent, Scotland Yard said, following the arrests.
Aged between 22 and 51, the men were held as “part of an ongoing investigation into Islamist-related terrorism and are not in response to any immediate public safety risk”, the force added.
Earlier this week, it was reported that Choudary said he has no sympathy for Alan Henning, a volunteer aid worker who was captured in Syria by Islamic State militants.
IS threatened to behead the 47-year-old in a video released earlier this month, which showed the murder of another British man, David Haines.
Choudary, who co-founded the now-banned group al-Muhajiroun, is reported to have said: “In the Qaran it is not allowed for you to feel sorry for non Muslims. I don’t feel sorry for him.”
He has also had contact with a number of worshippers who have later gone on to be convicted of terrorism.
Fanatics Michael Adebolajo and Michael Adebowale, who were both jailed earlier this year for the brutal slaying of Fusilier Lee Rigby, were both seen at demonstrations organised by al-Muhajiroun.
Choudary said he knew Adebolajo, who was pictured beside him at a rally in 2007, and the second founder of the group, Omar Bakri Mohammed, claimed that he had spoken to the future killer at meetings.
Al-Muhajiroun, which has changed names a number of times, was banned in the UK in 2010, and a study suggested that in the preceding 12 years 18% of Islamic extremists convicted of terror offences in the UK had current or former links with it.
Anti-extremism campaigners Hope Not Hate welcomed the arrests.
The group’s chief executive Nick Lowles said: “For over a year, since our own extensive investigations into Anjem Choudary and his disciples, we’ve been saying that more must be done to curb this hate-supporting and recruiting organisation.”