A series of explosions during rush hour this morning in Central London at underground tube stations and on double-decker buses has claimed the lives of several commuters and injured more than 100. The city’s transport system is now completely shut down as rescue teams and investigators clear the scene.

Although it’s not yet known who is responsible for the explosions, British Prime Minister Tony Blair has called the incident a terrorist attack and suggested it was aimed at disrupting the G8 Summit in Gleneagles, Scotland, this week.

“It is particularly barbaric that this has happened on a day when people are meeting to try to help the problems of poverty in Africa, and the long term problems of climate change and the environment,” Blair said. “Just as it is reasonably clear that this is a terrorist attack, or a series of terrorist attacks, it is also reasonably clear that it is designed and aimed to coincide with the opening of the G8.”

Blair has returned to London to deal with the incident, but said in a statement from Gleneagles at 1 p.m. BST: “We will not allow violence to change our societies or our values nor will we allow it to stop the work of this summit. We will continue our deliberations in the interest of a better world.”

Interestingly, oil prices — which reached $62 per barrel yesterday for the first time — have plunged following news of the explosions.