What could a terrorist gain by killing civilians? Nothing, unless, they assume publicity is an end in itself.
It will be a long day for all those office workers and children who have been asked to stay where they are.

Interesting twist to the use of mobile phones. BT is seeing a surge in the use of fixed line phones, as mobile phone networks are jammed.
Check the blogs from the London underground. One blogger on that blog network is keeping her chin up:

"Well as we’ve won, let’s just be thankful than this didn’t happen on the day that the Olympic inspectors were in town.."

Thanks to these citizen journalists we get live reports. This picture, for instance, of Bus number 59, near Russell Square station.