David Cameron launched a stinging attack on Gordon Brown today, saying there was a "thread of dishonesty" running through his premiership.
He described the apparent postponement of the next spending review as an attempt to "cover up the truth about Labour's cuts".
The Tory leader said the move was part of the Government's "pattern of deception" in the recent row over future spending on public services.
Business Secretary Lord Mandelson indicated today that the Government would not set out new public spending plans before the next general election, arguing it was currently impossible to forecast the economy two years ahead.
But Mr Cameron, speaking at a Westminster press conference, said: "Cancelling the spending review is nothing to do with economic uncertainty and everything to do with political manoeuvring.
"It is a blatant attempt to cover up the truth about Labour's cuts."
Lord Mandelson's intervention today came after weeks of rowing between Labour and the Tories about the need for spending cuts after the next election.
Mr Cameron said that Mr Brown had shown a "complete lack of respect for the people of this country" because he had not been frank about the challenges facing Britain.
He accused the Prime Minister claiming that spending on public services would rise when the Government's own figures showed it was going to fall.
"We shouldn't be surprised," he went on. "I believe there is a thread of dishonesty running through this premiership.
"From cancelling the election and then saying it had nothing to do with the opinion polls, to his claim that abolishing the 10p income tax (rate) would have nothing to do in terms of hitting the poor.
"We've had his insistence that Alistair Darling is his first choice as Chancellor, and now this frankly pattern of deception about public spending."
Mr Brown was today launching a new national plan for public services, called Building Britain's Future, as he seeks to regain the political initiative.
But, in view of Lord Mandelson's comments about the spending review, Mr Cameron said: "Today we've got a relaunch without a spending tag."