At least seven suspects have already been arrested under anti-terrorism laws and alert levels have been raised nationwide.
Just days after taking over from Tony Blair, British Prime Minister Gordon Brown is facing a major test, with the country on maximum alert and potential terrorists who may be linked to Al-Qaeda on the loose.
Brown told the nation on July 1 that Britain will not be intimidated.
"And I think the message that's going to come out from Britain and from the British people is that as one, we will not yield, we will not be intimidated, and we will not allow anyone to undermine our British way of life," he said.
The three intended attacks failed and no one was killed.
'A Sustained Threat'
But Home Secretary Jacqui Smith said Britain faced a "serious and sustained threat of terrorism" as she urged the public to remain alert.
A major break in the investigation came on June 30 when police arrested the driver and passenger of a Jeep Cherokee after it crashed into the entrance of Glasgow Airport, causing a major fire.
The gas canisters in the Jeep failed to explode -- allowing the police to capture the would-be suicide bombers and avoiding what could have been a major tragedy inside the packed airport terminal.
Police soon linked the Glasgow attack to another two car bombs that failed to detonate in London the day before. Those cars, packed with fuel canisters, propane tanks, and nails, were found parked near a crowded nightclub in the capital's busy theater district.
The British authorities have provided few details as they race to find more suspects. Two more arrests were reported today, bringing the total to seven.
Media reports say those arrested are of Middle Eastern origin. Gordon Brown has linked the failed attacks to Al-Qaeda. But as David Claridge, a senior security analyst with the London-based Risk Advisory Group, points out, just how close the connection is remains unclear.
Al-Qaeda Connection Unclear
"What the prime minister said is that it seems very likely that this is in general connected to Al-Qaeda," Claridge told RFE/RL. "That's probably the best way to describe at least what we know publicly at the moment. At the very outside, it may be a group that is acting with the general purpose and aims of Al-Qaeda or it may emerge over time that this is much more closely connected to Al-Qaeda. But at this moment we don't know where on that spectrum we're sitting."
What is clear is that the primitive methods used by the would-be attackers point to a network lacking in funding or sophistication.
"We know that there were some gas cylinders inside all of the vehicles concerned," Claridge said. "I don't know what was intended to initiate those gas cylinders. What is clear is that they did not explode. Whether or not it was just an attempt to ignite petrol with some shrapnel -- nails -- around it in the hope that they would pierce the gas canisters and cause an explosion or whether there was some more sophisticated detonator involved, I don't know. But what is clear is that they were so low-tech that they failed."
At least one British newspaper, "The Sun," reported that one of those arrested was a medical doctor of Iranian nationality. That has not been confirmed.
Claridge told RFE/RL that although Shi'ite Iran is not usually linked to Al-Qaeda, which is an extremist Sunni group, a connection might be possible -- although he cautions that even if one of the suspects turns out to indeed be Iranian, this does not prove any link to the authorities in Tehran.
"There have been some rumors in the past that Al-Qaeda has Iranian connections or at least has been tolerated by the Iranians or the Iranians have in the past used Al-Qaeda as a tool, if you like," Claridge said. "Whether or not those rumors are accurate is very hard to say. There are and have been a number of people under house arrest for some time -- senior Al-Qaeda figures -- in Iran and there have been rumors, again, that these house arrests are rather succor and support. But I don't think the presence of an Iranian national is evidence of some deep-seated Iranian connection with Al-Qaeda."
Strength Through Unity
Community leaders of all faiths in Britain have condemned the attempted terror acts. Ghayasuddin Siddiqui, director of the Muslim Institute, appealed to the Muslim community to come forward and help the police with their investigation. He told RFE/RL it should be remembered that the vast majority of Muslims in Britain were repulsed by what he called these "despicable" acts.
"There are, of course people who believe in this extremist ideology, but these are a small number of people, and we need to make sure that the bulk of Muslim community is not affected and their collaboration remains a top priority," Siddiqui said.
Home Secretary Smith, in a statement to the House of Commons in the late afternoon, said the government welcomed the statements against extremism from community leaders as she appealed for public unity.
"Terrorists attack the values that are shared by all law-abiding citizens," Smith said. "As a government, as communities, as individuals, we need to ensure that the message of the terrorists is rejected. I very much welcome the strong messages of condemnation we've heard throughout the weekend from community leaders across the country. It is through our unity that the terrorists will eventually be defeated."