Terror alert.

It seems that here in the UK we are at the second highest level of terror alert, in other words an attack is more or less imminent.
This raises more questions than it answers
One. What makes the powers that be think somethings going to happen? I mean do they actually know something or did somebody have a bad dream last night and thinks it might mean something.

Two. If it's intelligence based (and on past events that means nothing is going to be right, remember they shot a Brazilian electrician after "intelligence" said he was a bomber, and they also told us Saddam Hussein had weapons of mass destruction) then they presumably know who is going to do it, so why not just arrest them now and save all the messing about. After all it's a bit tricky to arrest a suicide bomber after the fact on account of him/her not actually being in one piece.

Personally (and call me suspicious) I think it's more lightly a load of old nonsense. You see you need to keep the public in fear if you want to get them to accept draconian laws that in "peace" time they never would. That means two things, one you have to make them think they are in danger if they don't have the laws, and worse sometimes you may need to make something happen to convince them they are in danger.
This either means letting the baddies do something to reinforce the "we told you so" attitude, or if it doesn't look like they are going to actually doing it themselves. Maybe those conspiracy theories are closer to the mark than we thought.