Why they can't charge Abu Hamza

Scotland Yard's difficulty in arresting extremists is in obtaining evidence that would stand up in court.

Police fear if they take figures like Abu Hamza and Omar Bakri Mohammed to court and fail to secure a conviction it only creates more propaganda. Officially the Yard says any alleged offence will be investigated.

The Yard did present evidence to the Crown Prosecution Service regarding Bakri, the leader of Tottenham-based Al-Muhajiroun, which wants to overthrow Western society and create a worldwide Islamic state. However, the CPS concluded it was not strong enough to bring a case.

Abu Hamza first aroused public anger in January 1999, when the Evening Standard identified him as the author of an internet site, Supporters of Shariah, advertising an "Islamic Camp" at Finsbury Park mosque.

Abu Hamza and two other men were arrested in March 1999, and held under the Prevention of Terrorism Act. However, they were all released without charge. At the centre of the Scotland Yard probe were allegations by Yemeni security officials said to link Hamza to a Christmas bomb plot against British targets in Aden.

Last October he was forced to relinquish control of the Finsbury Park mosque after a legal fight. Detectives have examined Hamza's comments and those of other militant mullahs to see if they have broken laws.

David Blunkett said: "They have so far been extremely careful to provide the maximum provocation with the care that is required for them not to be automatically picked up."