WASHINGTON – Just two days before yesterday’s horrific attacks on London’s mass-transit system, a British court began proceedings to deport a man widely believed to be Osama bin Laden’s envoy to the United Kingdom.

Abu Hamza al-Masri, a former Afghan Mujahedeen warrior turned Islamic scholar, stood in the dock on July 5 in London to hear the government he so often pledged to destroy make the case that he has urged fellow believers to kill Britons.

Terrorism experts yesterday were careful not to draw a link between the attacks and Mr. Masri’s case, saying the bombings were most likely linked to Al Qaeda’s campaign against the West, but in many ways the two matters are deeply connected. The Finsbury Park mosque, where Mr. Masri, 48, often gave fiery sermons imploring his faithful to defend Muslims against an assault from the West is widely considered to be the training and indoctrination ground for the jihadist movement in England.

“The leadership of the European Islamists relocated from Germany to England in the late 1990s. The Finsbury Park mosque was the central point, the embassy, the nexus for many of these groups. It served as both a recruitment and indoctrination school,” a Hudson Institute terrorism analyst, Christopher Brown, told The New York Sun yesterday.

A former CIA analyst and current chief executive officer for the Potomac Institute for Policy Studies, Michael Swetnam, yesterday said the Finsbury mosque likely played an important role in the London attacks.

“I would suspect that we will find that the Finsbury mosque and other ones like it were probably the centers of some of the recruiting for the attacks,” he said.

A British Web site, www.islamicnews.co.uk, features some of Mr. Masri’s sermons, in which he praised the “martyrs” of September 11, 2001, and warned that the faithful had access to weapons – even in Britain.

In 2003, British authorities began proceedings to strip Mr. Masri of his citizenship but ultimately decided not to extradite him to Yemen, where he is wanted in connection with a 1998 terrorist attack. British authorities in October opted to bring criminal charges against him, pre-empting an extradition request from America.

But despite the best efforts of three governments to prosecute Mr. Masri, he has remained at large until recently, giving speeches on the street outside the Finsbury Park mosque in London after the charitable commission that funds the mosque banished him last year. Mr. Masri, who has only one eye and no hands, faces a total of 15 counts against him.

Mr. Masri’s spokesman on Tuesday told the Associated Press: “From my point of view and Abu Hamza’s point of view, we don’t see Muslims as terrorists, we see the Western governments as the real terrorists.”

Mr. Swetnam yesterday pointed out that while British law allows its domestic intelligence agency, MI5, to gain surveillance warrants with fewer restrictions than American law, it is much harder for British authorities to detain and deport suspected Islamist militants. As a result, men like Mr. Masri, whose organization, Supporters of Shareeah, have explicitly defended the September 11, 2001, attacks and encouraged a defensive jihad against the West, are often allowed to roam the streets of Britain.

“We assume that Tony Blair has been with us on Iraq, and Britain has a robust counterterrorism strategy. But the British have a notoriously liberal perspective in interpreting laws on monitoring their radical Islamist elements,” a terrorism expert, Ilan Berman of the American Foreign Policy Council, said yesterday.

Shortly after the attacks yesterday, a group called the Secret Al Qaeda Jihad Organization in Europe issued a statement claiming credit for the bombings. But Messrs. Brown and Swetnam warned that initial claims of credit for terrorist attacks are often false. The director of the SITE Institute, which monitors radical jihadist Web sites, Rita Katz, yesterday told United Press International that most of the sites known to be affiliated with Al Qaeda have denounced the claim of responsibility as inauthentic. One American counterterrorism official told the Sun yesterday, “Al Qaeda, like Hezbollah, has perfected the art of setting up Potemkin organizations to claim credit for their work in order to confuse the media and investigators. I would not believe this group.”

Nonetheless, terrorism experts have reason to believe that the attackers were affiliated with Al Qaeda, just not the hitherto unknown group that claimed credit.

For example, the style of the attacks, marked by blasts in remote locations only minutes apart, is reminiscent of both the September 11 attacks and the 1998 bombings of American embassies in Africa. Also, Al Qaeda’s deputy, Ayman al-Zawahiri, warned of attacks on financial centers in the West in a February 20, 2005, audio recording.

“We think just about a year before the Madrid bombing, Al Qaeda went to a loose command and control structure,” Mr. Swetnam said. “They now give loose guidance to sympathetic groups who pick up on general speeches from the leadership. … They lack a command and control system we saw in Afghanistan.”

Another reason Mr. Brown at least believes this was an Al Qaeda attack is that terrorists in November 2002 were arrested by MI5 for attempting to poison underground commuters with cyanide. “We know that Al Qaeda often returns to targets later,” he said, pointing out that the September 11, 2001, attacks on the World Trade Center occurred after Al Qaeda operatives failed to blow up the towers in 1993.