Yay Kav's Okay!
I never know what to say when stuff like this happens. Anything I could say just seems so empty. So here is my best shot, don't laugh at me.
We're with you London.
Update: Kav has an excellent plan for the UK in responding to these attacks.
Update: There has been lots of stuff around about the date, and how it will be added to the list of infamous dates. 3.11, 9.11 and now 7.7. I can't help wondering if they intentionally stayed away from 7.11. (NOT that a terrorist attack on any day is okay obviously.)