A short time ago, the British government released two reports -- here and here -- on the July 7, 2005 terrorist bombings in London, which killed 52 and injured over 800. The reports suggest that more interrogations and more wiretaps may have thwarted the attack, as Gary Schmitt explained in the Weekly Standard:
If there is any smoking gun when it comes to the failure of British intelligence and the July 2005 bombings, it's the fact that there appears to have been knowledge of [subway bomber Mohammad Sidique] Khan's role as a possible al Qaeda fellow traveler among the post-9/11 detainees in both Pakistan and Guantanamo. What is known for sure is that Khan had traveled to Pakistan in 2003 and late 2004. And while he was only one of several hundred thousand U.K. residents who visited Pakistan for a month or longer in 2004, at least one detainee, and perhaps a second, subsequently recognized Khan and knew about his efforts to reach out to Muslim extremists while there.
In addition, the government's report takes note of the fact that in the run-up to the bombings themselves, the terrorists appeared to be in relatively constant phone contact with an individual or individuals in Pakistan. Although "it is not known who this was or the content of the contacts," according to the report, "the methods used, designed to make it difficult to identify the individual, make the contacts look suspicious."
Of course, it is impossible to know whether, if these "leads" had been followed up, the bombings would have been prevented. Nevertheless, the irony here is what would have been required to crack the case--information gained from detainee interrogations and from listening in on calls made to terrorist suspects abroad. Both are practices pushed by the Bush White House and roundly reviled by London's elite.
Based on the reports' findings, it's a good bet the British used more aggressive intelligence gathering techniques to help unravel the current bomb plot. And the British (and the U.S. for that matter) need all the help they can get if this report is accurate.