The summit will improve people's lives, Mr Darling says
Chancellor Alistair Darling has hit back at claims the rescue deal for the world economy agreed by G20 leaders will have little impact at home.
He insisted it would protect British jobs and "shorten what would otherwise be a long and painful recession".
The Tories welcomed parts of the deal but said it would seem "remote" to firms starved of credit and not alter the "mess" the public finances are in.
The Lib Dems said G20 pledges must be turned into "real help" for people.
'Part of a process'
Announcing a $1 trillion boost for the global economy agreed by the G20, prime minister Gordon Brown said a "new world order" of global economic co-operation had emerged from the summit.
Mr Darling defended the measures - which include support for struggling economies, credit to support trade and tougher financial regulation - from opposition criticism they would do little to help people in fear of losing their jobs right now.
Boosting trade was one of the best ways of supporting jobs, he said, because the UK depended heavily on global trade.
"Everything we do is about jobs," he told the BBC's Today programme.
"It is about trying to shorten what otherwise would be a long and painful recession."
Mr Darling admitted some of the financial help pledged by the G20 would take time to have an effect but he was "very clear that it would have an effect".
"This is part of a process which will will help us ensure we can protect jobs and that there are jobs there when we get into the recovery."
"You can't oversell what happened yesterday but you can't undersell it either," he added.
Mr Darling acknowledged unemployment was likely to continue rising in the coming months but he said ministers would do "everything we can to keep people in work".
Unemployment rose above the two million mark last month - its highest level since 1997 - and some experts believe it will have scaled three million by the end of the year.
The government accepted responsibility for "problems and shortcomings" in financial regulation over the past decade, the chancellor added, stressing these were now being corrected.
However, he said it was "ridiculous" to suggest Labour had allowed a form of "immoral capitalism" to take root.
He defended government intervention in the economy in the past 18 months, saying this contrasted with the Conservatives' "morally wrong" policy of letting the recession take its toll.
The Conservatives are backing the G20's decision to give more resources to the IMF to help poor countries as well as measures to regulate tax havens and bankers' pay.
However, they say the G20 communique vindicates their argument that countries can only plough amounts of money into their economies which they can afford.
The Conservatives argue the UK's rising debt levels mean it cannot consider a second fiscal stimulus package and say recent comments from Bank of England Governor Mervyn King - urging caution over further expansionary measures - backed this up.
"No trillion dollar boost for the IMF and trade finance will help us to deal with a trillion pound national debt that we are leaving to our children thanks to this government," said shadow chancellor George Osborne.
"The truth is Britain will be clearing up the economic mess created by this government long after the G20 show leaves town."
The Lib Dems said Gordon Brown had "passed the test" he had set himself as G20 host but stressed that much work was needed before the event could be called a success.
"He must now prove that he can turn this deal into real help for British people," said its leader Nick Clegg.
"To close the gap between his rhetoric and lack of real action Gordon Brown must urgently close the massive loopholes in the British tax system and force British banks that are owned by the taxpayer to finally start lending to British businesses."
"Families who are bearing the brunt of this recession will be unforgiving of the G20 leaders if their promises do not translate into real help."
The SNP said the summit showed the value of global co-operation but the leaders' promises must be be translated into action.
"This summit will not be judged now, but on whether the recession is short and shallow or deep and drawn-out," said the party's shadow Scottish Office spokesman Angus MacNeil.
"And now, after all the globetrotting and grandstanding, Gordon Brown needs to come back down to earth and get on with helping households and high streets across the country."