Anti-terrorism officers arrested six men in London in dawn raids today.
The six were arrested on suspicion of inciting terrorism overseas and raising funds for terrorists and included Abu Izzadeen who was caught on television heckling British Home Secretary John Reid at a public meeting last year.
The suspects were held "in low key operations" at 5am at five addresses in London and one in Luton, north of the capital.
A security source said the arrests were not related to the July 7th, 2005, suicide bomb attacks by four British Islamists in London that killed 52 people or any other major counter-terrorism operation.
Mr Izzadeen, who was born Trevor Brooks in Jamaica, shot to prominence when he heckled Mr Reid during a speech to Muslim leaders last September, urging them to root out extremism.
He has not been accused of any crime over that outburst but was charged by police earlier this year with encouraging terrorism during a speech he gave in Birmingham in 2006.