Re: Ah but...
Commswonk wrote: [...] what is the bien pensants reaction going to be if there is another 7/7 or Lee Rigby? I think I can hear it now: "Why didn't the police do something to stop it?" The answer may be "we didn't have the necessary powers" and it will be very hard to argue against that.
That answer would be a lie. They already have the necessary powers. They just want more - they will never say they need fewer powers - and they are willing to use any emotive situation to manipulate public opinion.
The perpetrators of the 7/7 atrocity were either already known to, or could and should have been linked to persons already known to the security services. In the case of Lee Rigby's murder, both were known to the security services. In neither case they did adequately act upon intelligence already in their possession.
One could postulate that the security services already had too much information with which to work, and that finding useful intelligence in a morass of information is almost impossible. Providing them with even more information would clearly be the wrong thing to do.