As seems to be happening with the UK "chemical" scare
Intelligence behind raid was wrong, officials say
(Guardian, 6/6/2006)
To be clear, I think it's vastly more likely that the British authorities screwed up (and shot a man in the process) than that there was any deliberate deception. However, it does fit with the point that these antiterror raids have often amounted to a lot less than first meets the eye.
