Douglas Ross, the most senior Tory north of the border, said the Prime Minister should ‘of course’ quit if he did not abide by the standards of conduct expected of ministers.
Several probes are under way into the tangled financing of the costly refurbishment – including an investigation by Mr Johnson’s new adviser on ministerial interests, Lord Geidt.
The PM is pictured together with Douglas Ross on a visit to Elgin, Scotland in the 2019 election campaign
But the PM, as head of the Government, will be the final adjudicator on any breaches of the ministerial code.
Mr Ross was asked on BBC1’s The Andrew Marr Show if Mr Johnson should quit if found to be in breach of the code.
He replied: ‘Of course, I think people expect the highest standards of those in the highest office of the land, that’s why I think people are looking at the investigations that are currently ongoing and waiting for the answers.’
Mr Ross is the most senior Tory to question the funding arrangements, putting him at odds with No 10.
His comments are likely to infuriate Downing Street, which has sought to play down the row. Foreign Secretary Dominic Raab yesterday dismissed claims that a Tory donor was asked to pay for a nanny for Mr Johnson’s one-year-old son Wilfred as ‘tittle-tattle’.
Douglas Ross, the most senior Tory north of the border, said the Prime Minister should ‘of course’ quit if he did not abide by the standards of conduct expected of ministers
The Sunday Times reported that senior Conservatives said donors have been approached about funding other aspects of the PM and Carrie Symonds’ lifestyle.
One donor is alleged to have said: ‘I don’t mind paying for leaflets but I resent being asked to pay to literally wipe the Prime Minister’s baby’s bottom.’
Mr Raab said he had ‘no idea’ if the claim was correct, adding: ‘You don’t have conversations like that with the PM.’
A No 10 spokesman said the Prime Minister ‘has covered the cost of all childcare’, but did not say whether he paid for the original bill himself.
The Foreign Secretary declined to deny a claim that a second invoice for the renovations may have been settled with the supplier by a Tory donor.
Mr Raab also sidestepped questions over whether Mr Johnson should resign if he is found to have broken the law by the Electoral Commission.
The Electoral Commission last week launched an investigation into whether any donations or loans were properly declared. It is also the subject of an internal review by the Cabinet Secretary Simon Case, and there have been calls for the Parliamentary Standards Commissioner Kathryn Stone to investigate.
Mr Johnson last week said he has now paid the £58,000 cost overrun and described the row as a ‘farrago of nonsense’.
Shadow Foreign Secretary Lisa Nandy said yesterday: ‘We need to know who the Prime Minister is beholden to, we need to know what he has promised in return.’
Mr Johnson’s chaotic decision-making has led No 10 insiders to nickname him ‘Trolley’, according to the BBC.
One source said: ‘You think you are pushing it along a path towards your goal then suddenly it veers off disastrously.’
Downing Street has declined to comment on the name.