Well the London Police Forces recently went down a security level, to the 'Second Level of Alert' which is still quite high, but not as high as it was in the past 5 years. Where the security level has been at it's highest. 1500 of the police force in London were also sent to the G8 summit. But that was a rather small ammount considering the London Police force has over 30000 personel.
Stocks are going down worldwide, and some repair work needs to be done before the London Train system is fully operational, and it really sucks for me, as some Australian people were critically injured. At least they're not dead however.
A witness, who was on the bus, just before it exploded, reported seeing a suspicious man who was very edgy, and holding a bag, containing something. Obviously this is probably the culprit, and very possibly, he blew himself up in the process. Hopefully the police can uncover the rest of this mystery. :P