The complex funding arrangement to cover the lavish refurbishments of Boris Johnson’s Downing Street flat has been detailed in an official report.

More than £28,000 was spent on painting and sanding floorboards to come close to the annual allowance afforded to the Prime Minister for renovations.

But additional invoices came in and were paid for by the Cabinet Office before being recharged to the Conservative Party in July last year, according to the report.

In March, the supplier – reportedly interior designer Lulu Lytle – refunded the Government, which then refunded the Tories, before Mr Johnson met “all final costs”, the report detailed.

The refurbishments to the flat in No 11 sparked sustained scrutiny of the Prime Minister’s finances and he was investigated by his own ministerial standards adviser, Lord Geidt.

Dominic Cummings, the Prime Minister’s hostile former chief adviser, had alleged that Mr Johnson planned to have donors “secretly pay” for the revamp in an “unethical, foolish” and “possibly illegal” plan.

Lord Geidt found Mr Johnson acted “unwisely” in allowing the refurbishment to go ahead without “more rigorous regard for how this would be funded”, but did not breach the ministerial code.

The standards adviser said Mr Johnson had not been aware Tory donor Lord Brownlow initially had settled an invoice for the works.

Fresh details of the funding arrangements were detailed on page 209 of the Cabinet Office’s annual report, published on Thursday.

The report says: “The Cabinet Office has a £30,000 budget each year for the upkeep of the dwellings within No 11 Downing Street.

“During 2020-21 Cabinet Office spent £28,647 with Mitie Facilities Management Limited at the request of the Prime Minister, which included painting and sanding of floorboards.

“Additional invoices for the refurbishment work undertaken on the No 11 Downing Street residence were received and paid for by the Cabinet Office and subsequently recharged to the Conservative Party in July 2020.

“In March 2021, the supplier refunded the Cabinet Office, and the Cabinet Office refunded the Conservative Party, with all final costs of wider refurbishment met by the Prime Minister personally.”