The way I see it, this could be -
1/ Complete fabrication, to take the heat off Blair (we'll never know, will we?)
2/ Complete fabrication to allow the furtherance of a British police state. People have been saying we're heading for a police atate for 40 years. Apart from the plethora of speed cameras, I don't feel my life has changed.
3/ A fair reaction based on inteligence. If the inteligence is incorrect, so be it, everyone makes mistakes. Did't intel from the Pakistan authorities trigger this (I may be wrong on this)?
4/ A fair rection based on accurate inteligence, in which case charges will be brought when all the evidence is gathered. I wouldn't expect the authorities to declare their hand if a) they are still collecting evidence or b) they are spreading the net further to catch more potential terrorists.
I'd expect things to become clearer in the next few weeks.