Abubaker Deghayes, who now runs the mosque in Brighton and whose brother Omar is a detainee at Guantanamo Bay, told an undercover reporter that he endorsed the views of George Galloway, the Respect MP, who said an attack on the prime minister by a suicide bomber could be morally justified. Deghayes said he prayed for Allah to support anyone who attacked Blair.

Court documents show Deghayes took over the mosque using violence, intimidation and threats. Dr Abduljalil Sajid, a leading imam and a government adviser on Islam, was forced out as head of the mosque by Deghayes and his supporters.

It is understood Sussex police Special Branch held a number of meetings with Sajid about extremist elements at the site, but no overt action was taken. Sajid, chairman of the Muslim Council for Religious and Racial Harmony, is understood to have raised his concerns about the mosque with Blair.

Police sources have confirmed that in the past extremist literature had been found at the site and that some of those attending the mosque were suspected of having fought as “mercenaries” abroad.

The Charity Commission, which has jurisdiction over the mosque because it is run as a charity, said it did not know how the mosque was receiving and spending money and added that it was operating “in breach of legal requirements”.

A reporter spent two weeks undercover at the Al-Quds mosque, which is in a detached house in Brighton. On Fridays, it can attract 100-200 worshippers. Deghayes made his extremist views clear while chatting to the reporter. Asked whether he shared Galloway’s view that the prime minister was a legitimate target for suicide bombers, he replied: “Yes, I do, I do.”

In another conversation, Deghayes said: “He is a legitimate target. Him and Bush are part of all that we see now.”

Later asked if he ever prayed for Blair to be attacked by a Muslim, he said: “I pray to Allah to support them. Of course, I know anybody who attacks in the name of Islam, Allah will take care of him.”

Deghayes also said he was unconcerned about British troops being killed in Iraq because the issue was “all clear in international law”. “Under international law anybody who’s been invaded, they are entitled to self-defence,” he said.

“It’s something all countries are signatories to. So what’s happening is an occupation. People in Iraq have every right to liberate themselves.”

But he urged the reporter to be careful with whom he discussed his views for fear of prosecution. Deghayes said: “Don’t talk openly, like ‘Tony Blair (is) an open target’. Now you can be taken in for glorifying terrorism.

“(Even) among Muslim brothers . . . there are hypocrites, munafiqs (hypocrites). There are spies, all sorts of people. There’s no need to talk about it, to say like this.”

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