Recession 'worse than predicted'

He also warned that the deal struck by Gordon Brown and other world leaders at London's G20 summit last week would only be effective if countries stuck to their promises.

Mr Darling refused to reveal by how much he will be forced to revise growth predictions in this month's budget amid forecasts that the economy could shrink by as much as 3% this year.

That would make 2009 the worst single year since the Second World War and three times the slide he steeled the country for in November's Pre-Budget Report (PBR).

"It's worse than we thought," he said in a frank admission that was seized on by the Tories as proof of a "record of incompetence" that would be exposed on April 22 when the Budget is delivered.

"When the Chancellor made his recession forecast last autumn, we - along with almost every independent forecaster - said it was likely to be wrong, but they wouldn't listen," shadow chancellor George Osborne said.

"The result is that unemployment will be higher, borrowing will be greater and the recovery more difficult. Budget Day looks like being the day when Labour's failures are finally laid bare."

Mr Darling said the depth and duration of the global downturn had taken people by surprise worldwide and pinned some of the blame on poor trading figures in the Far East.

"I thought we would see growth in the second part of the year," he told the Sunday Times. "I think it will be the back end, turn of the year time, before we start seeing growth here."

Asked if a 3% contraction was about what he expected, he told the BBC: "I am not going to get into what I am going to be predicting in a couple of weeks' time. But if you look at what has happened, the downturn since last autumn has been far deeper than I think people expected in any part of the world."