Boris Johnson’s top civil servant only became aware of proposals for a trust to fund the refurbishment of Downing Street months after the plans had already been formed.
The prime minister‘s revamp of his private flat above Number 11 is subject to a formal inquiry following claims a Conservative donor may have initially funded the works.
And it has now emerged that Cabinet Secretary Simon Case – who is also reviewing how the renovation was paid for – spent months in the dark about a possible funding scheme for revamping Downing Street.
The Cabinet Office has confirmed Mr Case, who began his role in September last year, only became aware of plans for a Downing Street trust in "late February".
This is despite work on the establishment of a trust having begun in spring 2020, while the government has claimed it engaged with Labour leader Sir Keir Starmer’s office on the proposals in July last year.
The revelation will raise questions about why Mr Case – whose role allows him to advise the prime minister on government policy, as well as propriety and ethics – had not been given prior knowledge of the plans.
The Times reported on Wednesday that Mr Case had resolved to find out more after reading an article on 27 February which said Mr Johnson had considered asking Conservative donors to fund the refurbishment.
A Cabinet Office spokesperson said: "The cabinet secretary only became aware of the trust in late February."
Mr Case subsequently met with crossbench peer Lord Powell of Bayswater and Labour’s Baroness Jay of Paddington on 11 March.
The spokesperson said this was to "discuss the facts around the trust, their involvement to date, the future of the trust and its viability".
"They did not discuss matters relating to historic funding," they added.
Both Lord Powell and Baroness Jay are said to have been approached by Conservative donor Lord Brownlow about becoming trustees.
In leaked emails, it recently emerged that Lord Brownlow offered the Conservative Party a £58,000 donation last year.
The money, according to emails seen by the Daily Mail, was to "cover the payments the party has already made on behalf of the soon to be formed ‘Downing Street Trust’".
In the emails to Conservative Party officials from October, the Tory peer was also reported to have mentioned a £15,000 donation.
However, only the £15,000 donation has been listed on Electoral Commission records, with mystery surrounding the other £58,000 sum.
Both Number 10 and the Conservative Party have not denied reports that Conservative Campaign Headquarters paid the Cabinet Office to cover initial costs of works on the prime minister’s flat.
The Cabinet Office said Mr Case’s review would now "establish the facts of what has happened" and that he would now "pass those facts to Lord Geidt for him to provide any advice to the prime minister that he deems necessary."
But they stressed Cabinet Office officials have been engaged and informed throughout and official advice has been followed.
Lord Geidt – a former private secretary to the Queen – was last week appointed as the prime minister’s new independent adviser on ministers’ interests and is also "ascertaining the facts" over Mr Johnson’s flat redecoration.
Mr Johnson has said he "covered the costs" of his flat redecoration, although he has not answered questions about who might have paid an initial invoice for the works.
Meanwhile, Scottish Conservative leader Douglas Ross reiterated his claim that, if Mr Johnson is found to have breached the ministerial code over the refurbishment row, then he should resign as prime minister.
"There are, I think, now three separate investigations going on into that situation," Mr Ross told Sky News.
"There are questions that need to be answered but I was also clear that those who seek and hold the highest office in the land have to hold the highest standards.
"It’s a big if and there are many investigations to get to that, but I’ve said if the prime minister has breached the ministerial code he could not continue."
Mr Johnson’s former chief aide Dominic Cummings recently alleged the prime minister "stopped speaking to me" about the flat refurbishment in 2020.
Mr Cummings claimed he had previously told Mr Johnson that "plans to have donors secretly pay for the renovation were unethical, foolish, possibly illegal, and almost certainly broke the rules on proper disclosure of political donations if conducted in the way he intended".