World leaders have condemned the attacks in London on Thursday in which three bombs blasted through the London Underground and one on a packed bus as commuters travelled to work.

Prime Minister Tony Blair said, "It is reasonably clear there have been a series of terrorist attacks.

"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, the long-term problems of climate change and the environment. Whatever they do, it is our determination that they will never succeed in destroying what we hold dear in this country."

Blair spoke on behalf of world leaders at the G8 summit when he said, "We condemn utterly these barbaric attacks. We are united in our resolve to confront and defeat this terrorism."

Other world leaders have also spoken out against the attacks. Spanish Prime Minister Jose Luis Rodriguez Zapatero issued a statement from his office, in which he offered the United Kingdom its "full support".

"Spain, which has suffered the scourge of terrorism, both national and international for years, offers its immediate and unconditional help, as well as its full support to the United Kingdom to pursue the criminals that have carried out such a repulsive attack."

Pope Benedict XVI called the attacks "barbaric acts against humanity" and said he was praying for the families of the victims.

Other world leaders have also spoken out against the attacks, Hungarian Prime Minister Ferenc Gyurcsany saying, "It's not acceptable that innocent people, children or adults, should suffer in London, or anywhere else in the world, because of the unacceptable terror of a few."

Dutch Prime Minister Jan Peter Balkenende meanwhile said that "Vigorous cooperation in the European Union and worldwide is crucial in order to meet this evil head on."

Condemnation has also come from the EU, Javier Solana, EU Foreign Policy Chief issued regret over the unpredictable nature of terrorist attacks.

"A terrible event can happen at any time. We cannot let down our guard. We are working every day, and in a coordinated way in all EU countries. Unfortunately there are times when one cannot prevent one happening."

The attacks come at a particularly poignant time with the United Kingdom holding both the presidency of the EU and the G8.

Sky News has put the latest death toll at 45 with Times Online reporting around 1500 injured, 150 of which are seriously.