A few random thoughts:
1) How many of the 37 dead and however many hundred wounded were White? People don't realize that London is largely a Third World city now; the original Caucasian inhabitants of the city have been driven out into huge high-rises ringing the city or else up into Essex and Surrey and Hertfordshire.
2) I well remember the delays in getting to and from work and around the city when I was there in '91 and '92 due to the I. R. A. bombing campaign of the time. I also remember how the British government of the time blustered and swaggered and beat their chests like they're doing now, and in the meantime quietly and without fanfare opened negotiations with the I.R.A. that led eventually to the Good Friday Agreement.
3) The United Kingdom is a vehicle with one engine, economically speaking, and that's London. The other major industrial cities like Manchester and Liverpool and Sheffield and Birmingham have been allowed to decay. The U. K. simply cannot afford to have London shut down, and there is really very little they can do about it in the face of a determined enemy. My guess is those British troops will be gone from Iraq in a year's time. They'll find some plausible excuse, but Tommy Atkins is coming home, mark my words.