If the latest round of explosions does turn out to have been another attempt at mass killing, British authorities could face plenty of sleepless nights ahead. They could portend a large network of potential bombers still at large in the country, capable of striking again. And once again, the normally capable British security services don't appear to have had any warning despite being on the highest state of alert.
RISKY ALLIANCE. Multiple incidents of this sort will also raise questions about Prime Minister Tony Blair's close cooperation with the Bush Administration in the war on terror, including contributing the largest number of troops after the U.S. to Iraq's occupation. Blair's popularity has been damaged by the Iraq war, and for a while he was under pressure to step aside in favor of Chancellor of the Exchequer Gordon Brown.
But recent events, including his cool handling of the July 7 bombings, have silenced such calls. The opposition party leaders even commended him in Parliament -- a rare occurrence.
But polls show a large majority of the public believes that Blair's policies have put Britain in the firing line of terrorists. Blair was stunned when Chatham House, probably Britain's most respected foreign policy thinktank, recently released a report saying "the U.K. is at particular risk because it is the closest ally of the United States, has deployed armed forces in the military campaigns to topple the Taliban regime in Afghanistan and in Iraq, and has taken a leading role in the international intelligence, police and judicial cooperation against al Qaeda and in efforts to suppress its finances."
Britain is unlikely to back away from its policies under threat of bombings and other attacks. But more such incidents would undoubtedly increase doubts about Blair's judgment.
NOT JUST ONE-OFFS? So far Londoners have handled these incidents with remarkable aplomb. Dark joking about entering a danger zone are common among subway passengers when they descend into the Tube. But an isolated incident is one thing. Repeated attacks could exact a stiff toll on the city, Europe's key financial and commercial center and a finance rival to New York.
The bombers seem to have found a vulnerable spot: The transportation system that moves millions of people across the city each day. If Londoners come to think of these attacks as possibly frequent occurrences rather than horrific one-offs, patterns of life, business, even the London economy could be profoundly changed.
Intercommunal tensions might also rise. Already the discovery that all four of the suspected July 7 bombers were British Muslims has raised serious questions about the workings of the local Muslim community.
LEGISLATIVE MOVES. At first glance the three suspected bombers from the Leeds area, who were all of Pakistani ancestry, seemed the most ordinary of young men, interested in soccer, helping other children, and other normal pursuits. But it also turns out that they fell under the influence of Islamic radicals either in Britain or on visits to Pakistan, or both. If these youths were either sufficiently disaffected or fired up by religion to be willing to blow themselves up in order to kill other strangers on trains, a big question arises: How many more from similar backgrounds might be persuaded to do the same?
Rapid progress by the British police in probing the July 7 bombings has certainly helped to buoy local confidence. Not only were the police able to quickly identify the bombers, who they say were all killed, they also think that the Pakistani authorities may have the mastermind in custody.
But if today's attacks turn out to be al Qaeda-linked or -inspired, unease could return again. And Britain's longstanding role as a hub for people from the Middle East and Islamic worlds could be under threat. Already the government is moving to enact legislation that would consider incitement of terrorism a crime and make it easier to deport fire-breathing imams. It would be sad if London, one of the world's most dynamic cities, is forced into a siege mentality.
Reed is BusinessWeek's London bureau chief