As many as 400 more armed police could be patrolling London after last month's massive anti-terror operations in the capital raised fears the police were being over-stretched.

The move came as Whitehall officials disclosed that three militant Islamists including the founder of al-Muhajirious, Omar Bakri Mohammed, face prosecution for allegedly inciting attacks on Britain and on British troops in Iraq last week.

The Attorney General, Lord Goldsmith, and Director of Public Prosecutions, Ken MacDonald, are closely scrutinising their remarks in television interviews for evidence that they justified and condoned attacks on British targets.

The law officers are considering common law offences of treason, incitement to treason and solicitation to murder, as well as criminal offences of with-holding information about terrorism and soliciting people to withhold information under the 2000 and 2001 Terrorism Acts. A spokeswoman for Lord Goldsmith said: "The Attorney Goldsmith and the Director of Public Prosecutions are considering comments that have been made by individuals during the week."

Two of the men, Abu Izzaden and Abu Uzair, appeared on a BBC Newsnight programme last week and refused to condemn the suicide bombings.

Omar Bakri Mohammed, a Jordanian closely linked to several of Britain's most militant Islamist groups, suggested in one Channel Four interview that it was acceptable for Muslims to attack British and American troops in Iraq.

He also appeared to condone acts of terror in Britain by foreign Muslims, such as Iraqis, on the grounds they believed they were under attack in their home countries.