Oh, and --
The threat level has been reduced twice in the weeks before major attacks.
The last time the threat level was reduced to “substantial” was in May 2005 after the security services assessed that investigative leads from the Crevice plot to attack the Bluewater Shopping Centre and Ministry of Sound nightclub with a homemade fertilizer bomb had been “followed up and discounted.”
The assessment was criticised when it emerged that two of the bombers who struck two months later had been on the fringes of that plot.
The threat level went up to “critical” after the July 7 attacks but went back down to “severe” in the days before the failed attacks of July 21.