Britain's new prime minister Gordon Brown confronted an immediate test of his leadership this weekend after a succession of failed car bomb attacks underscored a change in tactics by terrorists who authorities say are linked to Al Qaeda.
Five people, including one woman, were under arrest Sunday in connection with an apparent plot to detonate car bombs in London and Glasgow – the first time the car bomb tactic has been "imported" to Britain from Iraq, where it has been employed to grisly effect.
Though the latest, low-tech plots weren't foiled by British police intelligence, the lack of fatalities and amateurish construction of the bombs implies attackers with less training than Iraqi bombmakers.
"It's a different tactic in the UK, but it's not a different tactic for the global terrorist movement," says Bob Ayers, a security expert with London's Chatham House, an international policy think tank. "It's an application of a tactic that has been successful elsewhere."
Britain's terror alert level was raised to "critical" for the first time in almost a year, and security measures were redoubled at airports, crowded public spaces, and even on roads, with cars facing spot police checks. Police were combing houses in Glasgow and Liverpool, as well as closed-circuit television footage for further clues. One man was arrested in Liverpool yesterday; two were detained in northwest England on Saturday night, including one woman; and two men were held in Glasgow, including one in critical condition with severe burns.
No one was killed when two men rammed a fuel-laden jeep into a Glasgow airport building during a busy Saturday afternoon. Two cars were discovered packed with combustible materials and nails in central London on Friday night.
Terrorism experts noted that the failed attacks occurred close to the anniversary of the July 7, 2005 subway and bus bombings that killed 52 commuters, but added that they were more likely conceived as a test for Mr. Brown, who took over as prime minister just five days ago.
Brown responded by giving his first televised interview since taking power, in which he served notice that security was being ratcheted up at airports and in crowded places. But he vowed that Britons would not change their way of life because of the threat from "people who are associated with Al Qaeda."
"We are dealing with a long-term threat. It is not going to go away in the next few weeks or months," he said. "It's very important that people carry on living their lives as normal, to send a message to the terrorists that they will not be allowed to undermine our British way of life."
On Sunday, Homeland Security Secretary Michael Chertoff said there were no plans to change US security levels. "At this moment we don't have a specific credible threat against the United States," he said. But some US airports and mass transit systems are tightening security ahead of the Fourth of July holiday, according to the Associated Press.
British security services are monitoring the activities of as many as 2,000 radicals they suspect are capable of terrorist attacks. They cite as motivating factors: anger over the Iraq war, disenchantment with economic prospects, and an active conveyor belt that sends young Britons – many of Pakistani descent – through indoctrination camps in south Asia before returning them home again.
Some say the security services have been coming to grips with the threat, particularly since the 7/7 attack. Peter Neumann, a terrorism expert at King's College London says that the degree of desperation in the weekend attacks could be seen as a sign that the authorities were gaining the upper hand over terrorists.
Two weeks ago, seven men were found guilty of involvement in an Al Qaeda-linked plan that, among other things, intended to use a limousine filled with gas canisters as a car bomb. In the only other successful mass prosecution of Islamic militants in Britain, a group was convicted in April of planning a series of attacks on a nightclub, shopping center and gas network. [Editor's note: The original version mischaracterized the prosecution of terrorists in Britain.]
This past weekend's car bomb attacks, for example, did not appear to have been planned or executed with the same sophistication as 7/7, or the other plots that British authorities say they have recently disrupted.
"The fact that they were trying to attack the terminal building is an indication that it has become harder to get on the plane and disrupt the actual traffic," Mr. Neumann says.
But Neumann adds that there were several worries for the security services: the attacks apparently came with no prior intelligence, one of the London cars was spotted by an ambulance crew that noticed smoke coming from a car, and the Scotland attack was apparently unexpected in that it was assumed terrorists were only interested in London targets.
Mr. Ayers agreed that the fact that no one was killed should not be interpreted as a success for Britain's counter-terrorist effort. "Let's not credit the security services for Friday night's attack; let's not credit them for the Glasgow attacks," he says. "They were failures as a result of incompetence" on the part of the perpetrators.
Lord Stevens, a former police chief appointed last week to the new post of adviser on international security issues, wrote in a newspaper column: "It is a sign of the new maturity and sophistication of Al Qaeda in Britain that they have moved to this car bomb-style campaign. "Make no mistake, this weekend's bomb attacks signal a major escalation in the war being waged on us by Islamic terrorists."
MJ Gohel, another London-based security expert, says that car bombs are easier to make than the fertiliser bombs and other explosive devices used in previous British attacks and plots.
"The materials are easily obtained [and] available in the open market. The method is described on the Internet, and it doesn't require high level sophistication," he says. "But these vehicles are lethal weapons of mass destruction," he says, adding that hundreds could have died in London or Glasgow if the weapons had worked as they were intended to.
That they didn't was probably due to the amateurish execution. Lord Stevens drew parallels with car bombings in Iraq and Bali, but the British versions were a poor imitation. The cars used a combination of nails, gasoline, and gas canisters, and none detonated.
Bombs in Iraq, by contrast, typically use high explosives, such as C4 or explosives scavenged from old Iraqi weapons depots. The first Bali attack, in 2002, used about 200 pounds of ammonium nitrate, a fertilizer, to make a bomb similar to the one that destroyed the Alfred P. Murrah federal building in Oklahoma City in 1995, while the second Bali bomb was reported to have used TNT.
Yet defending against car bombs will prove taxing, Mr. Gohel adds. "The police can't stop and search every vehicle [entering London]. "
Dan Murphy contributed from Cairo.