A report published on Friday by Lord Geidt, the independent adviser on ministers’ interests, said Prime Minister Boris Johnson had acted “unwisely” by allowing “the refurbishment of [his] apartment at No. 11 Downing Street to proceed without more rigorous regard for how this would be funded.”

Geidt’s investigation found that the work on the flat had initially been paid for by Lord David Brownlow, who covered the cost directly with the supplier on October 22, 2020. However, Johnson apparently did not become aware of who had paid for the refurbishment until media reports raised concerns in late February.

The report accused Johnson of a “significant failing” for not ensuring that the Trust, which deals with the refurbishment of the PM’s official residence, was “subjected to a scheme of rigorous project management by officials.”

However, the Tory leader avoided any penalties, with Geidt concluding that, despite Johnson not asking enough questions about the source of the funds, “no conflict (or reasonably perceived conflict) arises as a result of these interests.”

Johnson came under heavy criticism earlier this year after reports that the initial costs of refurbishing his official flat in Downing Street was covered by a Conservative Party donor. It is thought the total cost of the work ran up to £200,000 ($283,280), despite the prime minister only having an annual public grant of £30,000 ($42,490) to carry out such renovations.

The Electoral Commission has launched a separate investigation into how the refurbishment was funded, claiming there are “reasonable grounds to suspect that an offence or offences may have occurred.”