How serious WAS the UK plot?

There have been some odd questions floating around regarding the foiled UK bomb plot-- how close was the plan to fruition? Did a White House desperate for "good" news pressure authorities to move before they were ready? Were the new security measures justified? That last question came to the forefront after fighter jets were scrambled to escort a plane diverted because of a woman's anxiety attack. Now conservative pundit Andrew Sullivan is taking the questions even further, and he's not alone.

So far, no one has been charged in the alleged terror plot to blow up several airplanes across the Atlantic. No evidence has been produced supporting the contention that such a plot was indeed imminent. Forgive me if my skepticism just ratcheted up a little notch. Under a law that the Tories helped weaken, the suspects can be held without charges for up to 28 days. Those days are ticking by. Remember: the British authorities had all these people under surveillance; they did not want to act last week; there was no imminent threat of anything but a possible "dummy-run," whatever deranged guest-bloggers at Malkin say. (Correction, please.) Bush and Blair discussed whether to throw Britain's airports into chaos over the weekend before the crackdown occurred.

Sullivan also cites a former British ambassador:

None of the alleged terrorists had made a bomb. None had bought a plane ticket. Many did not even have passports, which given the efficiency of the UK Passport Agency would mean they couldn't be a plane bomber for quite some time. (. . .)

What is more, many of those arrested had been under surveillance for over a year - like thousands of other British Muslims. And not just Muslims. Like me. Nothing from that surveillance had indicated the need for early arrests.

Then an interrogation in Pakistan revealed the details of this amazing plot to blow up multiple planes - which, rather extraordinarily, had not turned up in a year of surveillance.

I'd hate to learn that this is like recent US "terror plots" that collapsed under scrutiny, especially given the sweeping changes in air travel rules and the disturbing implication that Britain is complicit in this administration's record of lying about threats for political gain. Even worse, right-wingers are using the story to justify torture and searching all Arab and Muslim travelers at airports. Extremism in response to dubious threats has been the hallmark of the Bush era, and we'll be paying the price as a nation for a very long time.