A Tory donor provided more than £52,000 to cover some of the costs of Boris Johnson’s lavish renovations to his Downing Street residence, according to party accounts.

The refurbishments to the flat in No 11 sparked sustained scrutiny of Mr Johnson’s finances, with the works vastly exceeding the £30,000 annual limit afforded to the Prime Minister.

Conservative Party accounts published on Thursday said its central office provided a “bridging loan” of £52,802 to cover the works after being invoiced by the Cabinet Office in June last year.

The party was “reimbursed in full” by Lord Brownlow in October, before Mr Johnson “settled the costs” incurred by the Conservative peer in March.

Labour deputy leader Angela Rayner said: “These latest revelations prove that the Prime Minister appears to be allergic to telling the truth about the dodgy dealings and the web of conflicts of interests, secret loans and cover-ups that hang over him like a bad smell.”

Revealing the details on page 25 of the 26-page accounts, the Conservatives pointed to a review by the Prime Minister’s own ministerial standards adviser, Lord Geidt.

He 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 that Lord Brownlow had initially settled an invoice for the works.

A Cabinet Office report in July said more than £28,000 was spent on painting and sanding floorboards, coming close to the limit of public funding.

But additional invoices came in and in March the supplier – Soane Britain, which is owned by interior designer Lulu Lytle – refunded the Government, which then refunded the Tories, before Mr Johnson met “all final costs”, the annual report detailed.

Dominic Cummings, the Prime Minister’s 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, which No 10 denies.

A Tory spokesman said: “As stated, the party provided a short-term bridging loan that was reimbursed to the party in full.”