Number 10 has refused to deny reports that Conservative donors were approached to pay childcare costs for Boris Johnson’s son.
At the weekend, an MP was claimed to have received a complaint from a Tory donor that they were asked to foot the bill for Mr Johnson’s one-year-old child Wilfred with his fiancee, Carrie Symonds.
According to the Sunday Times, 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."
Asked about those reports at a briefing for Westminster journalists on Tuesday, the prime minister’s official spokesman said Mr Johnson had "covered all the costs of all childcare".
Pressed on whether the money was out of the prime minister’s pocket or from donors, the spokesman said he had "nothing more to add".
And, when asked whether donors had been approached to pay for childcare – even if they didn’t end up paying – the spokesman repeated: "The prime minister has covered all costs of childcare."
Labour called on Mr Johnson to publish correspondence "relating to all attempts to get Tory donors to fund the prime minister’s lifestyle".
The party’s deputy leader, Angela Rayner, said: "We are seeing what looks like another cover-up from the prime minister, who is trying to hide his attempts to fund his lifestyle through secret payments from wealthy Tory donors.
"Boris Johnson forcing his MPs to vote against free school meals and making stealth cuts to schools at the same time as asking Tory donors to pay for his own childcare is yet more evidence that it’s one rule for him and his mates another for everyone else.
"What did these donors expect in return for their generosity, and what were they promised?
"With an investigation already under way into potentially illegal activity, the prime minister and Conservative Party should stop taking the British people for fools and immediately publish all correspondence relating to all attempts to get Tory donors to fund the prime minister’s lifestyle."
Asked on Monday whether a Conservative donor was ever asked to pay for childcare, Mr Johnson said on a by-election campaign visit to Hartlepool: "I can tell you that all this kind of stuff is, in my view, exclusively for the interest of the Westminster bubble.
"And I find that what people want to talk about is the issues that matter to them in this election, and that is overwhelming."
Meanwhile, Foreign Secretary Dominic Raab dismissed the claims as "tittle-tattle".
Last week, the Electoral Commission announced it had launched a formal investigation into the prime minister’s revamp of the flat he shares with Ms Symonds.
The watchdog said there were "reasonable grounds to suspect that an offence or offences may have occurred".
As prime minister, Mr Johnson earns £157,372 per year.