Welling-born radical preacher Anjem Choudary is understood to be one of nine men arrested today as part of an investigation into Islamist terrorism and a banned organistion with links to Lee Rigby's killers

The men, who were all seized in London, were arrested on suspicion of being members of, or supporting, a banned organisation, the Met Police said.

Al-Muhajiroun is understood to be the banned organisation in question, sources told the Press Association.

Counter-terrorism police are searching 18 addresses across London, and one in Stoke-on-Trent.

The men, who are aged between 22 and 51, were arrested as "part of an ongoing investigation into Islamist-related terrorism and are not in response to any immediate public safety risk", Scotland Yard said.

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.

Islamic State (IS) militants 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 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."

Choudary, who co-founded the now banned group al-Muhajiroun, has 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 in Woolwich, 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.

The group, 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.

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 moved out about a week ago.

She said Choudary had lived there for around two years and claimed there was police activity at the weekend after he left.

The woman, who did not wish to be named, said: "There were police cars and officers walking around. I can't say whether they actually went in."

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."