Ministers have rejected criticisms of the $50bn (£28.8bn) aid package agreed at the G8 summit.
Prime Minister Tony Blair insisted "very substantial progress" had been made in helping developing countries.
International development secretary Hilary Benn said: "This is politics demonstrating its capacity to make a difference."
And campaigner Bob Geldof was satisfied the measures agreed on Africa would save 10 million lives.
Mr Blair acknowledged the shortcomings in what the summit had achieved saying: "We do not, simply by this communique, make poverty history."
But he said the G8 had demonstrated a "political will " to end global poverty and to tackle the effects of greenhouse gas emissions.
On climate change, Mr Blair said an agreement had always been unlikely, but that the US now accepted global warming was an issue.
Environment Secretary Margaret Beckett said claims the G8 offered nothing new on climate change were "absolute rubbish".
Some aid agencies and environmentalists have described the outcome of the summit as "vastly disappointing".
"The people have roared but the G8 has whispered," said Kumi Naidoo, chair of the Global Call to Action against Poverty.
Yet Live 8 organiser Bob Geldof spoke of a "great day".
"Never before have so many people forced a change of policy onto a global agenda. If anyone had said eight weeks ago will we get a doubling of aid, will we get a deal on debt, people would have said 'no'," Mr Geldof said.
He added that he gave the G8 summit "10 out of 10 on aid, eight out of 10 on debt".
Irish rock star and fellow anti-poverty campaigner Bono, praised the agreement to give universal access to Aids drugs.
"600,000 Africans, mostly children, will remember this G8 summit at Gleneagles because they will be around to remember this summit, and they wouldn't have otherwise," said Bono.
- Mr Blair said trade discussions in Hong Kong later this year should yield an end date to agricultural subsidies.
- Britain is to host a 1 November meeting on climate change, to assess progress.
- Mr Blair said "only people who can change Africa ultimately are the Africans".
- $3bn agreed for Palestinian Authority for investment in infrastructure.
- Nigeria's President Olusegun Obasanjo described the deal as a "success".
- G8 commits to training 20,000 peacekeepers for Africa.
- African leaders to commit to democracy and good governance as part of the deal.
- Debts of the 18 poorest countries to be forgiven.
- Universal access to anti-HIV drugs in Africa by 2010.
Summing up the G8 meeting, Mr Blair acknowledged: "It isn't all everyone wanted, but it is progress."
UN Secretary General Kofi Annan said the G8 deal represented a "good day", but that it was only "a beginning".
"The fight to end poverty is just starting," said Mr Annan.
On climate change, Mr Blair said: "If it is impossible to bring America into the consensus on tackling the issue... we will never ensure the huge emerging economies, who are going to consume more energy than any other part of the world... are part of the dialogue."
He said however that agreement had been reached that climate change was a problem, human activity contributed to it and it had to be tackled with urgency.
'Face of death'
Earlier the prime minister had said that in the wake of Thursday's attacks, the communique was the "definitive expression of our collective will to act in the face of death".
"It has a pride and a hope and a humanity that can lift the shadow of terrorism," he added.
Non-Governmental Organisations (NGOs) remained critical of the G8 deal.
Some described the talks on climate change as a "significant lost opportunity".
WHAT IS THE G8?
Group of eight major industrialised states, inc Russia
Canada, France, Germany, Italy, Japan, Russia, UK, US
G8 leaders have indicated the statement represents progress but Stephen Tindale, a spokesperson for Greenpeace, said: "The G8 has committed to nothing new but at least we haven't moved backwards on the environment."
The Sustainable Energy and Economy Network, a worldwide coalition of environmental and development campaigners, said: "Urgent action is now required to substantially reduce emissions, reduce fossil fuel dependence and to protect people around the world, especially the vulnerable, the poor and disappearing nations."