Experts call for cuts immediately after 2010 election but Labour says it will not withdraw fiscal stimulus until 2011

A score of eminent economists today attacked the government's strategy to tackle the budget deficit as not "credible", calling for cuts to begin as soon as the general election is over.

The government is adamant it will not begin to pay off the deficit until 2011 and Labour has made it a crucial point of difference with the Tories that it will not withdraw the fiscal stimulus prematurely.

David Cameron has said a Conservative government would hold an emergency budget within 50 days, but the Tory leader has indicated that there would not be "swingeing cuts" immediately.

By contrast, 20 economists who signed a letter to the Sunday Times, including four former members of the Bank of England's monetary policy committee, call for spending cuts immediately after the general election. They argue that there is "a compelling case" for politicians to begin to tackle the deficit this year, and predict that failure to so do could lead to a loss of confidence and threaten recovery.

The letter reads: "In the absence of a credible plan, there is a risk that a loss of confidence in the UK's economic policy framework will contribute to higher long-term interest rates and/or currency instability, which could undermine the recovery … In order to be credible, the Government's goal should be to eliminate the structural current budget deficit over the course of a parliament, and there is a compelling case, all else equal, for the first measures beginning to take effect in the 2010-11 fiscal year."

Tim Besley, a professor of economics at the London School of Economics and until last year a member of the Bank of England's monetary policy committee, organised the letter. He said: "I don't want this to be seen as us siding with anyone. But it does suggest that the Conservatives are where majority opinion lies."

Other signatories include Lord Turnbull, Sir Howard Davies, Ken Rogoff, Thomas Sargent and the Labour peer Meghnad Desai, who has previously criticised the prime minister as "weak and indecisive". Explaining his decision to lend his name to the letter, Desai said: "Right now we have got a fragile recovery but as soon as conditions allow, somebody will have to tackle the structural deficit with which we started the recession.

"Obviously during a recession you have to spend extra money, the deficit has to go up to get rid of unemployment. But once all that has passed us, we will have to tackle this because we can't go on borrowing money."

The letter came as reports emerged at the weekend that the prime minister and the chancellor, Alistair Darling, are at odds over how to position next month's budget. One Sunday newspaper reported Brown as being in favour of spending commitments as a "springboard" to the election, while Darling is said to favour detailing his proposals for bringing down public debt.