Boris Johnson failed to tell his most senior civil servant about the plans for his Downing Street refurbishment to be paid for by a charitable trust, according to reports.
Simon Case, who was appointed cabinet secretary in September, only discovered about the controversial plans in the newspaper.
The mandarin is now conducting a review and leading the fallout from the £200,000 refurbishment plans which Dominic Cummings claimed 'almost certainly broke the rules'.
Simon Case, who was appointed cabinet secretary in September, only discovered about the controversial plans in the newspaperInsurance Loans Mortgage Attorney Credit Lawyer
The Prime Minister has insisted he met the cost himself but has refused to say whether initial bills were paid by donors.
An Electoral Commission investigation is currently underway into allegations that donors were asked to pay for a redecoration of the flat Mr Johnson, 56, shares with fiancee Carrie Symonds and their son.
Case, who is leading a separate internal review, first learned of Johnson's plans after reading an article on February 27 which revealed the prime minister's alleged plans to ask Conservative donors to pay for the costs of the redecoration, The Times reports.
He then discovered that Lord Brownlow of Shurlock Row, a multimillionaire Tory donor, would become the chairman of a trust and had already offered trustee positions to members of the House of Lords.
The Prime Minister has insisted he met the cost himself but has refused to say whether initial bills were paid by donors
Brownlow had consulted Baroness Jay of Paddington, the former Lords leader and daughter of prime minister James Callaghan, and Lord Powell of Bayswater, a former adviser to Margaret Thatcher.
Powell said he received a call from Brownlow on February 11 but details were initially scant.
He claims Brownlow did not mention the trust might organist the redecoration of the private residence and said he did not know how it would be funded.
Jay said she was told it was the public part of Downing Street that would benefit from the refurbishment, not the private residence.Insurance Loans Mortgage Attorney Credit Lawyer
A Cabinet Office spokesman