Boris Johnson has attacked his own sister's claims about Brexit and hedge funds, branding them "absolute nonsense".
The Prime Minister went to war with sister Rachel after she voiced fears he was being influenced by "people who have invested billions in shorting the pound or shorting the country in the expectation of a no-deal Brexit ".
Remain-supporting Rachel, who has repeatedly clashed with her brother, made the allegations in a BBC interview last week.
But Mr Johnson told LBC radio this morning: "This is absolute nonsense.
"We are doing things to take forward the UK economy and to get growth into the UK economy.
"Look what we're doing with low pay - this is the biggest expansion of the living wage ever."
Pressed again on her claims that he is backed by speculators who bet billions on a hard Brexit, he said: "I'm not going to comment on whatever my sister may or may not have said.
"She's wrong.
"But I'm not going to get dragged into conversations about my beloved family."
The allegation has been prominent for around three weeks following an article by the Byline website.
The Byline article highlighted donations to the Tories by financiers who are also betting against - 'shorting' - certain firms or aspects of the economy.
It is certainly true that some financiers taking short positions have donated to the Tories or Boris Johnson . Crispin Odey, who made £220m overnight as sterling slumped in the 2016 referendum, is one, and the Mirror has reported on him previously.
However, fact-checking website Full Fact said the Byline article had used incomplete data and it was unable to identify a sharp rise in short positions that was alleged.
The Financial Times also argued the full picture was more complicated, with financiers taking many positions at one time and not only betting over Brexit.
The allegations were nonetheless repeated on the weekend by former Chancellor Philip Hammond.
Mr Hammond, one of 21 Tories who lost the whip for trying to block no-deal, wrote: "As [the PM's] sister has reminded us, he is backed by speculators who have bet billions on a hard Brexit.
"And there is only one outcome that works for them: a crash-out no-deal Brexit that sends the currency tumbling and inflation soaring."
