I was working at home today when I heard that there had been explosions on the London Underground. Initial reports said this was due to a power surge, but then I heard that a bus had blown up and it became obvious that something sinister was going on.

I'm fortunate in that I'm fairly sure that nobody I know was hurt today, but my sympathy goes out to those who have lost someone and to those who will bear the mental and physical effects for the rest of their lives. It often seems with a disaster that you hear plenty about the dead, but less about the survivors.

I hope this doesn't result in knee-jerk reactions like the USA did back in 2001. If we all have to change how we live then the terrorists have won. See Bruce Schneier's comments for a reasoned look at how terrorism should be handled. London is riddled with CCTV cameras, but that didn't stop this happening. Would ID cards have made any difference?