The decree has been issued by Omar Bakri Mohammed, chief of the Al Muhajiroun group during an interview with the BBC radio.

The decree urges Pakistan army not to support Musharraf, whom they labelled as "apostate". The army should punish him, he said.

"The fatwa calls on Muslims all over the world to stand together and support Muslims in Afghanistan and to reject the authority of Musharraf."

Meanwhile police has started inquiry against Bakhri over the alleged death threat he issued against Musharraf.

British Minister for Europe Peter Hain said last night he would ask the police to investigate whether Sheikh Omar Bakhri Mohammed, leader of the Al-Muhajiroun organisation, could be prosecuted under Britain's recently strengthened terrorist laws for his threat made in a radio interview yesterday.

Bakhri, who has been questioned in the past by Scotland Yard detectives about his behaviour, issued an apparent threat against Musharraf for supporting imminent American military response.

In his BBC radio interview the Syrian-born sheikh said, "The fatwa is calling on Muslims to stand together and support Muslims in Afghanistan and to reject the authority of Musharraf."

Asked if this amounted to a death threat, he said, "The fatwa itself declares, yes. Musharraf is (an) apostate and, therefore, Muslims in the army should not support him. They should punish him for his crimes."

Sheikh Omar told 'The Times' last night "Musharraf is guilty of condoning the invasion of Afghanistan. He predicted that a Pakistan army general would kill his own leader as it was his religios duty to do so".