Yeah,just about every square inch of london is monitored by CCTV. The only problem is,this can not really prevent a suicide bomber from jumping on the tube or from getting on a bus. It will in time show us who probally did it (An arab looking fella) but it really does not prevent what as already happened. You also cant go around stopping every arab carrying a bag.
All day long people are leaving bags on the underground and public transport and nobody batters an eye lid. I think people will obviously be abit more aware of their surroundings now though.
As for the I.R.A., even though they are no better, there was always a warning before the bombs went off and as you said was mostly millatary targets or property.
I have no doubt that the terrorist will soon be identified,but as I said its not like the guy could be brought to justice.
All we can do is show these people that we will not change the way we live or run scared