http://www.nytimes.com/2006/08/28/world/europe/28plot.html?pagewanted=1&ei=5094&en=09d0e2102978e4b1&hp&ex=1156824000&partner=homepageDetails Emerge in British Terror Case
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But at the same time, five senior British officials said, the suspects were not prepared to strike immediately. Instead, the reactions of Britain and the United States in the wake of the arrests of 21 people on Aug. 10 were driven less by information about a specific, imminent attack than fear that other, unknown terrorists might strike.
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Later that day, Paul Stephenson, deputy chief of the Metropolitan Police in London, said the goal of the people suspected of plotting the attack was “mass murder on an unimaginable scale.” On the day of the arrests, some officials estimated that as many as 10 planes were to be blown up, possibly over American cities. Michael Chertoff, the secretary of the Department of Homeland Security, described the suspected plot as “getting really quite close to the execution stage.”
But British officials said the suspects still had a lot of work to do. Two of the suspects did not have passports, but had applied for expedited approval. One official said the people suspected of leading the plot were still recruiting and radicalizing would-be bombers.
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Another British official stressed that martyrdom videos were often made well in advance of an attack. In fact, two and a half weeks since the inquiry became public, British investigators have still not determined whether there was a target date for the attacks or how many planes were to be involved. They say the estimate of 10 planes was speculative and exaggerated.