Former director general Mark Thompson, who left the corporation last year, has accused BBC Trust chairman Lord Patten and trustee Anthony Fry of "fundamentally misleading" a parliamentary committee.
His attack comes in a written statement to the Public Accounts Committee ahead of Monday's hearing. It also describes Lord Patten and Mr Fry's committee appearance as containing "important inaccuracies".
Lord Patten and Mr Fry told the committee that members of the Trust were not always included in decision-making. Mr Fry said there was "some disconnect" between what Mr Thompson had written in a letter to the Trust about deputy director general Mark Byford's pay-off, in which he apparently said it was within contractual arrangements. The National Audit Office found it was not. Mr Byford left the BBC with £949,000.
Lord Patten said he was "looking forward" to coming back before the MPs and had "no concerns" about Mr Thompson's comments. He said he found Mr Thompson's statement "curious" for focusing on Mr Byford's pay-off, which he said was awarded before he became Trust chairman.
A Trust spokesman said it rejected "the suggestion that Lord Patten and Anthony Fry misled the PAC".
But Tory MP Rob Wilson said Mr Thompson's allegations "have blown a hole" in Lord Patten's claim the Trust was only responsible for 'strategy'.