Iain Duncan Smith arrives to attend a pre-Budget cabinet meeting in London | Leon Neal/ AFP via Getty Images Iain Duncan Smith: UK Treasury has no long-term economic plan The Brexit campaigner and former Tory leader says the Treasury has to be broken up.

LONDON — Former U.K. Cabinet minister Iain Duncan Smith launched a savage attack on George Osborne's Treasury Thursday, accusing it of being the “worst thing in Britain” and “characterized solely by a lack of vision.”

The leading Brexit campaigner and former Conservative Party leader — who sparked a furious row after quitting as work and pensions secretary in protest over proposed budget cuts — said Chancellor of the Exchequer Osborne’s finance department was damaging the British economy because of its “short term” obsession with making cuts.

“I think it has to be broken up, I have reached that conclusion,” he said.

Duncan Smith’s explosive intervention, undermining the government’s central claim that it has a “long-term economic plan,” came at an on-the-record, round-table discussion with journalists and leading political figures in central London Thursday.

Asked whether Britain’s decline in manufacturing required a much stronger interventionist role for government, Duncan Smith said some steps had been taken in this regard, but blamed the Treasury for standing in the way of more radical solutions because of its obsession with making savings.

Osborne has made reducing the U.K. government deficit the central focus of his tenure in the Treasury. In 2010 he vowed to eliminate the deficit by 2015, but only succeeded in halving it. He then pledged to run a surplus by 2020 and have the U.K.’s overall debt fall as a percentage of GDP.

Duncan Smith said the main problem for the U.K. economy’s long-term future was the power of Osborne’s department.

“The worst thing we have in Britain is the Treasury,” he said. “The culture of the Treasury is almost unique in the Western world that a country’s government is so dominated by one organization.”

He complained that the Treasury was dominated by junior civil servants who move jobs every couple of years, stopping any long-term decisions from being taken.

“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.”

Duncan Smith claimed this was not the case in the U.S. or Germany. He said the Treasury’s culture had always been bad but had deteriorated under the former Labour chancellor Gordon Brown, who held the position from 1997 to 2007.

“Gordon Brown at the Chancellor’s job just took over every department," he said. "There’s been a fight to push some of it back but its power is enormous at the moment.”

He said the power of the Treasury was harming the U.K.’s ability to make long-term decisions about its future.

“I just simply make the point that these kind of decisions that were made in Germany — and to an extent are being made in America and others — to try to revitalize industry are very difficult to be made with them parked in the middle of this, because it’s not a department that is characterized by the concept of vision.

“This is a department that is characterized solely by a lack of vision."

Insisting he didn't intend to sound "narrow and rather bitter," he described the Treasury's lack of vision as the "single most difficult thing,” adding that he breathed a "sigh of relief" when he left government because he would "never have to deal with those people again."

Duncan Smith said the U.K. needed to decide whether it wanted to be a leading country for manufacturing or not. The claim is particularly damaging because Osborne and the Prime Minister David Cameron pledged to “rebalance” the U.K. economy away from finance towards manufacturing in a “march of the makers.”