An official report into former defence secretary Liam Fox's links with his self-styled adviser Adam Werritty is expected to find that he breached the Ministerial Code of Conduct.
The findings of Cabinet Secretary Sir Gus O'Donnell - who was due to deliver his report to David Cameron on Monday night - will be published on Tuesday.
The Guardian reported the country's most senior civil servant will deliver a "damning" verdict on Dr Fox's conduct - while accepting that he had not personally gained financially from his relationship with Mr Werritty.
Dr Fox finally resigned on Friday amid a welter of allegations suggesting his close contacts with his best man and former flatmate breached Whitehall rules.
Sir Gus was last week ordered by the Prime Minister to take over an internal Ministry of Defence inquiry in an effort to provide answers to "all remaining questions".
An interim MoD report has already established that the then defence secretary had met Mr Werritty - who handed out business cards describing himself as Dr Fox's adviser even though he had no official role - 40 times since coming to office.
Their contacts included trips abroad and meetings at the MoD - including talks with the Israeli ambassador, dinner with the new US commander of international forces in Afghanistan, and a meeting in Dubai with a defence supplier without MoD officials present.
Sir Gus is not expected to make recommendations on ministers' contacts with lobbyists, as his remit was limited to establishing the facts about Mr Werritty's activities.
Downing Street has not said whether the report will be published in full or whether some details will have to be redacted, although officials have indicated that they intend to be as open as possible.
"We will be transparent about this," the Prime Minister's official spokesman said. "We have asked Gus O'Donnell to establish the facts and we will be clear about what those facts are. Gus has not been asked to make recommendations. He has been asked to establish the facts and that's what he will do."
An official report into former defence secretary Liam Fox's links with his self-styled adviser Adam Werritty is expected to find that he breached the Ministerial Code of Conduct.
The findings of Cabinet Secretary Sir Gus O'Donnell - who was due to deliver his report to David Cameron on Monday night - will be published on Tuesday.
The Guardian reported the country's most senior civil servant will deliver a "damning" verdict on Dr Fox's conduct - while accepting that he had not personally gained financially from his relationship with Mr Werritty.
Dr Fox finally resigned on Friday amid a welter of allegations suggesting his close contacts with his best man and former flatmate breached Whitehall rules.
Sir Gus was last week ordered by the Prime Minister to take over an internal Ministry of Defence inquiry in an effort to provide answers to "all remaining questions".
An interim MoD report has already established that the then defence secretary had met Mr Werritty - who handed out business cards describing himself as Dr Fox's adviser even though he had no official role - 40 times since coming to office.
Their contacts included trips abroad and meetings at the MoD - including talks with the Israeli ambassador, dinner with the new US commander of international forces in Afghanistan, and a meeting in Dubai with a defence supplier without MoD officials present.
Sir Gus is not expected to make recommendations on ministers' contacts with lobbyists, as his remit was limited to establishing the facts about Mr Werritty's activities.
Downing Street has not said whether the report will be published in full or whether some details will have to be redacted, although officials have indicated that they intend to be as open as possible.
"We will be transparent about this," the Prime Minister's official spokesman said. "We have asked Gus O'Donnell to establish the facts and we will be clear about what those facts are. Gus has not been asked to make recommendations. He has been asked to establish the facts and that's what he will do."