Boris Johnson is reported to have told his ministerial standards adviser that he did not disclose messages exchanged with a Tory donor about his flat refurbishment because they were on an old phone.
Letters between the Prime Minister and Lord Geidt are expected to be published on Thursday afternoon, but Mr Johnson is likely to be cleared again of breaching any ministerial rules over the funding of the redecoration.
Last month, the Electoral Commission revealed that Mr Johnson had sent Tory peer Lord Brownlow a WhatsApp message in November 2020 “asking him to authorise further, at that stage unspecified, refurbishment works on the residence”.
But Mr Johnson had previously said he had no knowledge of the payments until immediately prior to media reports in February 2021.
The investigation prompted Lord Geidt to demand clarification from No 10 amid claims that he had been misled by the Prime Minister.
And the Daily Telegraph and the Financial Times have reported that Mr Johnson said the reason he did not disclose the message before was that he had changed his mobile number, and therefore the WhatsApp message was on his old phone.
The Prime Minister’s official spokesman declined to say whether Mr Johnson has apologised to Lord Geidt.
Lord Geidt previously cleared the Prime Minister of breaching the code in relation to the funding of the flat refurbishment.
But the Electoral Commission fined the Conservatives £17,800 after it found the party had not followed the law over donations by Lord Brownlow to help cover the renovations, with costs exceeding £112,500.
The watchdog said the Tories had failed to “accurately report a donation and keep a proper accounting record” of the money handed over by the peer in October 2020.
Downing Street previously insisted that Mr Johnson had not lied to Lord Geidt, and the Telegraph said the adviser was to uphold his initial decision that no rules were broken.
But the newspaper reported he would express his dissatisfaction that he had not been provided with the messages before, and had not been made aware of them before the Electoral Commission investigation was released.