The incredibly reliable and competent guys who shot Jean Charles de Menenzes?

The point is they don't use the powers they have intelligently and appropriately. Asking for more powers and fewer restrictions is just a way of avoiding facing up to the mistakes they have made. And of course they needed to tell Tony Blair what he wanted them to tell him - that's how "intelligence" works with this administration. Here's an article about all this which is worth reading - Don't be duped by yet another dodgy dossier :

"Any MPs who hold misgivings about supporting an invasion on the basis of a dossier later discovered to have been utterly misleading ought now to be demanding a proper, transparent investigation into what the police did and did not do that might have prevented the bombings in London of July 7; and they ought to treat with extreme caution the "dossiers" prepared to support 90-day detentions."