Foreign Secretary David Miliband denied that the Government was in "meltdown" after another opinion poll showed the Tories extending their lead into double figures.
Mr Miliband insisted that ministers were getting on with the "serious business" of government as a YouGov poll for The Sunday Times put the Conservatives 13 points ahead of Labour.
The findings represent a return to the sort of lead the Tories enjoyed in the 1980s when Margaret Thatcher was in her heyday.
However, Mr Miliband - in Basra for the handover of control to the Iraqis - rejected suggestions that the Government was in terminal decline.
"It doesn't feel like meltdown at all. It is the job of headlines to come up with the drama. It is the job of government to do serious business," he told BBC1's The Andrew Marr Show.
"This is a Government getting on with the big and difficult decisions. Big and difficult decisions do arouse opposition, they do arouse concern.
"But I would be much more worried if this was a Government that wasn't grasping the difficult decisions, wasn't willing to do the things that are needed to move the country forward. In the end what counts are not headlines but ideas, and it's the ideas that this Government will in the end live or die by."
The YouGov poll put the Conservatives on 45%, up four points on last month, while Labour were down three on 32% and the Liberal Democrats up one on 14%.
The findings come at the end of a month dominated by the Labour proxy donor scandal, the loss of HM Revenue and Customs child benefit database, and continuing concerns about the economy.
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Mr Brown's own approval rating - the difference between those who say he is doing a good job and those who say he is doing badly - also slumped to minus 26%, down from minus 10% last month.
