Ed Balls suggested yesterday that the Conservative Party may have played a part in leaking his private papers charting Gordon Brown's attempts to dislodge Tony Blair as Prime Minister.
The documents, which surfaced in The Daily Telegraph, showed how Mr Brown's allies, including Mr Balls and Ed Miliband, began planning a swift and smooth Blair-to-Brown transition soon after the 2005 general election.
Last night, more documents were released highlighting advice from civil servants dating back to 2006 recommending that public spending should rise no faster than the rate of inflation and calling for inefficiencies to be cut. Critics said this showed Mr Brown had ignored advice prior to the credit crunch, which left Britain with a deficit. The documents also indicated Mr Brown was aware that abolishing the 10p rate of income tax would leave millions worse off, something he denied.
The papers may have been mislaid or stolen when Mr Balls, the former education secretary, moved out of the Department for Education's offices when Labour lost power in May last year. He last saw them on his desk shortly before the general election, ready to be moved to his Commons office if Labour was defeated. They never turned up but Mr Balls was not aware they were missing.
There was no explanation about why it took so long for the material to reach the public domain. But Labour figures claimed the Tories may have held it back to discredit the shadow Chancellor's attacks on the Coalition Government's failing economic policies.
"Whoever gave these papers to the Telegraph wants me to stop doing that and despite my frustration I refuse to let that happen," Mr Balls said yesterday.
After a request from Mr Balls, Whitehall launched an investigation, but it will not be a formal leak inquiry because the documents are not government papers. A statement said: "The Cabinet Office is looking first into whether this particular set of papers was in the possession of any government department. [And] if so, whether there have been any breaches of security within government."
The shadow Chancellor dismissed the Telegraph's claim that the papers revealed a "brutal" plot to oust Mr Blair. "There is nothing here to justify talk of a plot," he said, insisting the documents referred only to the attempt, agreed by Mr Blair and Mr Brown, to ensure a "stable and orderly transition" when the Prime Minister stepped down.
Balls aides said the only reference to "brutal" in the papers was in a Brown camp memo saying: "If we are to renew Labour, we have to be as rigorous and brutal as we were in the creation of New Labour."
Asked about Mr Brown's description of Mr Blair's ideas on the transition as "shallow", "inconsistent" and "muddled", Mr Balls admitted the changeover was not "always sweetness and light". He added: "There were times when their relationship was fraught."
In February 2006, in response to Mr Brown's repeated handover requests, Mr Blair wrote to him: "The division at the top is killing us." He told his Chancellor: "You (understandably) want to end the uncertainty by me going now," but said it would be "corrosive" if Mr Brown was seen to be "disloyal" or "too eager to get his hands on the job".
Mr Miliband dismissed the revelations as "an over-hyped version of history". He said: "Frankly, the era of Blair and Brown is over and we're a party looking outwards to the country, not looking inwards and talking to ourselves, and that's the way it's going to be under my leadership."
Michael Gove, the Tory Education Secretary, is confident that his department will be cleared of playing any role in the leak. His aides blamed the disclosure on Labour's bitter internal feuds.
Some Tories believe that a Labour figure leaked the papers to damage Mr Balls at a time when he is emerging as a pivotal figure in Labour and there is grumbling about Mr Miliband's performance as leader.