Alistair Darling moved to allay fears of a freeze on the pay of public-sector workers as unions warned that they should not be punished for the failings of the private sector. Downing Street and the Chancellor made clear that there was no question of reopening the three-year pay deals negotiated with the police, teachers and nurses, the third year of which is 2010-11.

David Cameron said there would be no blanket freeze on public pay under a Conservative government. Both the main parties, while preaching restraint, appeared anxious to avoid a clash with potential supporters and strike action from the unions that represent them.

When Mr Darling gives the Government’s evidence to the public sector pay review bodies in the autumn he will ask them to take account of the low rate of inflation in making their recommendations for the year 2010-11.

But sources close to him made clear that in an interview on Sunday he was neither “sending out a signal, trailing, nor hinting” that there would be a pay freeze. The sources added there was no possibility of current three-year deals being reopened.

Earlier a No 10 spokesman told reporters: “The Prime Minister shares the Chancellor’s view that public sector pay has got to reflect prevailing conditions, and in particular reflect the fact that inflation has come a long way down. Of course, we have got to be fair to people who work in the private sector as well as those in the public sector. But contrary to speculation that does not mean there are any plans to reopen multi-year deals.”

The Prime Minister shifted his tone on public spending, appearing to suggest that any increases were dependent on growth in the economy.

Speaking at the Anglo-French summit in Evian he said: “If we can get growth, if we can get unemployment down, if we can keep interest rates and inflation down, then there is scope to do the things we want to do, and that is to get money to the frontline services.”

Mr Brown spoke after Peter Hain became the latest minister to voice caution over spending. “Once we emerge from recession it is fair to state that a slower growth of public spending will be the best strategy,” Mr Hain said.

Mr Cameron, interviewed on the Radio 4 Today programme, acknowledged that pay settlements for public sector workers would be “much tighter” as the public finances were rebuilt. But, he said, a Conservative government would stick by the existing system of public sector pay review bodies.

Steve Bundred, the Audit Commission’s chief executive, had said that workers, including those in the NHS and education, would “tolerate” a freeze as they had “done well” over the past ten years.

When Mr Cameron was asked if he would order a freeze on public sector pay, he said: “I don’t think that is the way we do pay in this country.

“The way we do pay in this country in the public sector, rightly, is we have independent pay review bodies.”

The Conservative leader emphasised that in making recommendations, the pay review bodies would have to take account of developments in the private sector where many workers have had their pay frozen. “Those bodies do have to look at what is happening in the private sector, where pay levels are very restrained, because those pay review bodies are looking at how do we recruit, retain and motivate public sector staff,” he said.

“So, yes, you are going to see much tighter public sector pay settlements.”

Brendan Barber, the TUC General Secretary, said that there would be a “very strong reaction” if the Government attempted to “punish” public sector workers for the private sector’s problems. “We have seen a period in which there has been a real increase in investment in the public services. That’s not always been reflected in the pay and conditions of public service workers,” he told Today. “The idea that because the private sector has been facing such tough times we have almost got to punish the public service workers to ensure an equality of misery is absolutely wrong.”