A Muslim activist has been arrested in east London over allegations of encouraging terrorism.
Mr Izzadeen is being held at a central London police station
Abu Izzadeen was arrested in Leyton High Road by counter-terrorism officers, Scotland Yard said.
He hit the headlines last September after heckling Home Secretary John Reid but it is understood the inquiry is related to a 2006 speech in Birmingham.
Mr Izzadeen, 32, is being held at a central London police station under Section 1 of the Terrorism Act 2006.
He has been associated for some years with radical Islamist politics in the UK and has been a member of two now illegal groups, Al Muhajiroun and Al Ghurabba.
In September, Mr Izzadeen, who was born Trevor Brookes in London, interrupted Mr Reid's speech at the public meeting in Leytonstone.
Mr Reid was asking Muslim parents to keep a close eye on their children and act if they suspected they were being radicalised by extremists.
Mr Izzadeen shouted out: "Shame on all of us for sitting down and listening to him."
He said he was "furious" about "state terrorism by British police" and accused the minister of being an "enemy" of Islam before being led from the building by police and stewards.
A second heckler, who also interrupted Mr Reid's speech, was ejected a few minutes later.
The groups Mr Izzadeen has been associated with were banned last year under anti-terrorism legislation passed in the wake of the 2005 London bombings.
Al Muhajiroun had announced it was disbanding in 2004 although it was unclear whether its members were still meeting.
Its former leader, radical self-styled cleric Omar Bakri Mohammed, left the country following the London bombings.
Some of his followers established two new organisations, one of which was Al Ghurabba.
Mr Izzadeen became one of the group's main spokesmen and would willingly give interviews.
Little is known of the activist's early life other than his family are of Jamaican origin and he converted to Islam in early adulthood.
He has been a regular attendee at public events staged by radical groups in London.