Former work and pensions secretary Iain Duncan Smith has called for the Treasury to be broken up, branding George Osborne's department "the worst thing in Britain".
The former Cabinet minister said that the Treasury dominated Government decision-making but was characterised by a "lack of vision" and a "short-term" obsession with cuts.
Mr Duncan Smith - who walked out in March in a row with the Chancellor over benefit cuts - complained that other ministers have to "fight at all stages" with the Treasury over policy.
He said he gave a "sigh of relief" when he left government because he would "never have to deal with those people again".
His comments, reported on political website Politico, appear to contradict Mr Osborne's oft-repeated claim to be following a "long-term economic plan".
"The worst thing we have in Britain is the Treasury," said Mr Duncan Smith. "I think it has to be broken up, I have reached that conclusion,"
At a round-table discussion with journalists and political figures, the former minister reportedly complained: "The culture of the Treasury is almost unique in the Western world that a country's government is so dominated by one organisation."
"The average age in the Treasury is 27. They spend no more than two years in any single part of the Treasury. They have no collective memory for any agreement or decision that had been taken before they arrived at their desks.
"Everything is up for grabs immediately someone new moves in and they dictate every single policy area across government. It is a fight at all stages."
Mr Duncan Smith said that the Treasury's power over Whitehall was established under Labour chancellor Gordon Brown, leaving it with "enormous" power over other departments.
The kind of decisions made in countries such as Germany and the US to support industry were "very difficult" in the UK because of the Treasury's dominance, he said.
"It's not a department that is characterised by the concept of vision," he said. "This is a department that is characterised solely by a lack of vision."