He attacked the Conservatives as stuck in the past and called them the "do nothing, uncaring party".

"Doing nothing is not an option," he told Labour party members at the annual Progress conference in London on Saturday.

"This is the biggest New Labour project of all: to give people confidence and hope that we can build through this downturn into a better economy and society. It will mean not a slowing down of reform but only a stepping up in the pace of reform."

Outlining the major challenges that the world faces, he emphasised the need for a co-operative approach between countries, such as in tackling the economic situation.

"We've got a global financial system but we don't have global financial supervision of it. When you have global financial flaws and you only have national supervision of them, you inevitably run into the sort of problems that we have seen."

He also highlighted climate change, inequality and terrorism as major problems that must be addressed.

Referring to the attacks in Mumbai, he said: "A great multi-faith democracy has been laid low by terrorists."

He said it raised "huge questions" about how the world addresses violent extremism.

"Most of the problems that we face can't be solved in isolation," he said. "We are the first generation that has the chance to build a truly global society. We must be the generation that builds these global institutions and builds this global co-operation."