Gordon Brown has been accused of attempting to blackmail Tony Blair into dropping Adair Turner's revolutionary pension reform proposals.
The revelation - described in the final chapter, Endgame, of Blair's autobiography The Journey - centres on the ‘cash for peerages' scandal, with the Labour government accused of awarding peerages in return for private donations to the party.
In his recount of the events of 15 March 2006, the day the story broke, Blair talks of a morning discussion with Brown prior to a 4pm trilateral meeting with the then pensions secretary John Hutton to discuss the Turner commissions proposals.
"When Gordon came in [to the morning meeting], he was in a venomous mood," recalled Blair. "I can truthfully say it was the ugliest meeting we have ever had."
Blair then accuses Brown of threatening to launch an inquiry into the allegations unless the Turner's proposals - supported by the PM and the pensions secretary - were dropped.
He said: "What he [Brown] proceeded to say in the meeting stunned me. He began the conversation not by talking of pensions, but by saying how damaging the loans thing was; that there might have to be an NEC inquiry; and he might have to call for one. I naturally said that would be incredibly damaging and inflammatory and on no account must he do it.
"The temperature, already well below freezing point, went arctic he then said: ‘Well, it depends on this afternoon's meeting'.
"If I would agree to shelve the Turner proposals, he would not do it. But if I persisted, he would."
Blair goes on to recount how the Chancellor pointed to a translation of the Royal Irish Regiment's motto ‘Fotto a ballagh', which means ‘Clear the way', on his desk and said, "That's what you should do - clear the way."
An hour after of the meeting - in which Blair backed Turner's recommendations - party treasurer Jack Dromey called for an inquiry. Blair said Brown denied having spoken to Dromey.
Our weekly heads-up for advisers
'Nothing can prevent scammers developing workarounds'
Stalwart Scottish Mortgage takes third place
Consistency and compliance vs. slower reaction time
Search for replacement to begin imminently