It is "none of your business" how Boris Johnson paid for a lavish refurbishment of his Downing Street flat, a government minister has said.
The outburst by health minister Nadine Dorries comes amid growing questions about the PM's finances – and reports that he told aides he could not afford the work.
In a late-night post on social media Ms Dorries lashed out at a journalist who asked "where did he get the cash" when he was "supposedly broke".
The minister said: "You can legitimately ask, ‘was tax payers money used?’ Beyond that, it’s absolutely none of your business".
But opposition figures say it is important to know how Mr Johnson funded the work to make sure he has no conflict of interest.
Labour has called for the Electoral Commission to open an investigation into the PM and whether he should have declared a loan or donation.
When pressed on the issue cabinet ministers have refused to deny the the PM was fronted the cash by a wealthy backer as a loan.
The Daily Mail newspaper reports that when aides asked Mr Johnson after Christmas how much the work was costing, the prime minister said: "Tens and tens of thousands – I can’t afford it."
In reported comments apparently about his fiancé Carrie Symonds, he is quoted as saying: "The cost is totally out of control – she’s buying gold wallpaper!"
The claims tally with earlier reports dating from September last year that the prime minister was worried about money and considered himself to be broke.
Those reports claimed the prime minister was "subdued" and "miserable" about having to live on his £150,000 a year government salary – less than he earned from previous work.
The questions of the flat come amid growing questions about alleged cronyism and undue lobbying in Westminster.
