Islamist radicals who express support for terrorism may face treason charges, the Attorney General's Office has said.
Omar Bakri Mohammed is one of three who may be prosecuted
Lord Goldsmith and the Director of Public Prosecutions Ken Macdonald have discussed action against three individuals, a spokeswoman said.
The Crown Prosecution Service's head of anti-terrorism will meet Scotland Yard officers in the next few days.
Omar Bakri Mohammed, Abu Izzadeen and Abu Uzair are all expected to come under scrutiny.
The spokeswoman for the Attorney-General's Office said it was not clear at this stage whether there was enough evidence to bring charges.
Officials will be looking at broadcast and published comments as well as speeches and sermons made by the trip to followers.
"No decision on charges has been made yet. The CPS will be looking at it to see if any offences have been committed," she said.
Possible charges which will be considered include the common law offences of treason and incitement to treason.
Omar Bakri Mohammed is a London-based cleric for the al-Muhajiroun group.
On Friday while announcing new measures to clamp down on extremism, Prime Minister Tony Blair said that this group's successor organisation, the Saviour Sect, would be outlawed.
Mr Bakri caused controversy when he said he would not inform police if he knew Muslims were planning a bomb attack in the UK.
He also expressed support for Muslims who attacked British troops in Afghanistan and Iraq.
"For Muslims there, they have a duty to fight occupiers, whether they are British soldiers or American soldiers," he told Channel 4 News.
'Smell the coffee'
British-born Abu Izzadeen, a spokesman for the group al-Ghurabaa (the Strangers) has declined to condemn the 7 July London bombings.
He told BBC2's Newsnight the bombings were "mujahideen activity" which would make people "wake up and smell the coffee".
Abu Uzair, a former member of al-Muhajiroun, told the same programme that the September 11 attacks in the US were "magnificent".
He said Muslims had previously accepted a "covenant of security" which meant they should not resort to violence in the UK because they were not under threat there.
"We don't live in peace with you any more, which means the covenant of security no longer exists," he said.