LONDON — The bombings in London last week may mark the first strike by Osama bin Laden's terrorist network on a city that had already served as a catalyst and crossroads for Al Qaeda operatives involved in plots targeting the United States and other nations.
Radical members of London's large Muslim population have been linked to a series of plots, including the Sept. 11 attacks, the attempted shoe bombing of a transatlantic flight to Miami in December 2001 and last year's deadly train bombings in Madrid.
When Washington raised the U.S. threat level last August, it was after authorities acquired evidence that an Al Qaeda operative captured in Britain had conducted extensive surveillance of targets in the U.S., including Citigroup Center in New York and the World Bank offices in Washington. One of the suspect's aliases was "Al Britani."
And though Britain has passed aggressive anti-terrorism measures in recent years, allies have been frustrated by the country's seeming inability to detain or extradite Islamic firebrands. Spanish officials, for example, have criticized Britain for its refusal to extradite an extremist cleric known as Abu Qatada, described by a Spanish judge as Al Qaeda's spiritual leader in Europe.
As a result, Britain's counter-terrorism approach is described in somewhat contradictory terms. U.S. officials and experts praise the country's cooperation and capabilities, even while describing London as a haven for extremists.
"It's the paradox of the United Kingdom," said Roger Cressey, a former White House counter-terrorism official in the Clinton and Bush administrations. In Britain, Cressey said, "you have some of the most sophisticated law enforcement and intelligence operations. At the same time, London is easily the most important jihadist hub in Western Europe."
The classic trade-off between intelligence work and crime prevention also played a role in thwarting efforts to combat attacks. Britain's powerful spy agencies found North London's Finsbury Park Mosque a valuable surveillance post for watching Al Qaeda's web of contacts despite complaints of investigators in mainland Europe that London was a headquarters for directing attacks elsewhere, experts say.
Authorities have not yet determined who was responsible for Thursday's bombings. A group calling itself the Secret Organization of Al Qaeda in Europe claimed responsibility on a website. And investigators are increasingly focused on a theory that the strikes were the work of a homegrown terrorist cell that, at the least, was inspired by Al Qaeda.
British authorities disclosed Saturday that the three subway bombs went off within seconds of one another, suggesting a level of sophistication and coordination that has become a hallmark of Al Qaeda's attacks.
London's reputation as a haven for Islamic radicals has emerged over more than a decade, fueled by policies that included granting asylum to Muslim dissidents who were likely to be prosecuted in their home countries.
Saad Faqih, the controversial head of the London-based Saudi opposition group Movement for Islamic Reform in Arabia, praised the British government and people for being "very, very tolerant." Faqih is precisely the kind of dissident who has benefited from London's policies; he would be jailed in Saudi Arabia, and Washington considers him a terrorist. But in London, he runs a radio station and lives and works freely.
In an interview, he said the tolerant British were finally attacked to force them to divorce themselves from Washington. "They [the attackers] wanted to send a message, not just to England but to all of Europe, to disassociate itself from America," Faqih said.
Among radicals tolerated and even granted citizenship in Britain is Abu Hamza al Masri, who openly celebrated the destruction of the World Trade Center and preached hatred of the West from Finsbury Park Mosque -- all while living on social welfare payments.
The British government incarcerated him last year and is now trying to revoke his citizenship, which could lead to his extradition to the United States, where he is under an 11-count indictment charging him with terrorism-related crimes.
But other foreign radicals deemed dangerous by the government were released from prison after Britain's highest court ruled late last year that foreigners considered a security risk could not be imprisoned indefinitely without trial, a major setback to an emergency anti-terrorism law put in place by Prime Minister Tony Blair's government after Sept. 11.
Lord Leonard Hoffman, one of the judges on the court, said at the time that the law itself might constitute more of a threat to the British way of life than terrorism. "It calls into question the very existence of an ancient liberty of which this country has until now been very proud: freedom from arbitrary arrest and detention," he wrote.