The Guardianblog has updates:
This is on the BBC Website:
Two people have been killed and scores have been injured after three blasts on the Underground network and another on a double-decker bus in London.
[Blair] said it was "particularly barbaric" that [the attacks were] was timed to coincide with the G8 summit. He is returning to London.
An Islamist website has posted a statement - purportedly from al-Qaeda - claiming it was behind the attacks.
London's police chief Sir Ian Blair said there had been "many casualties" but it was too early to put a figure to those killed or injured.
More than 100 casualties and one of the dead were taken to the Royal London Hospital in Whitechapel.
And St Mary's Hospital said it was dealing with 26 injured people, including four with critical injuries and eight in a serious condition.
1 hour ago