David Cameron has accused Ed Miliband of “total and utter confusion” after it emerged that Labour will not seek to reverse the coalition's child benefit cuts.
The Prime Minister accused the Opposition leader of a u-turn after condemning the coalition's decision to strip payments from high earners.
Mr Miliband is expected to use a speech tomorrow to stress that the country's dire finances mean the party will have to make tough choices if it wins the general election.
He is expected to hint strongly that the child benefit changes will not be reversed, and also indicate that he supports some form of overall cap on benefit budgets.
The intervention, which follows the announcement by shadow chancellor Ed Balls that Labour would end winter fuel payments for better-off pensioners, is being seen as a further attempt by the party to rebuild its economic credibility.
But in angry clashes at Prime Minister's Questions in the Commons, Mr Cameron said: "The very first time the leader of the Opposition came to that despatch box he attacked me for taking child benefit away from higher earners.
"And yet today we learn it is now Labour's official policy to take child benefit away from higher earners. Total and utter confusion."
Video: PMQs battle over waiting times