Separately, inquiries are underway into thousands of pounds worth of taxpayer grants given to his former mistress Jennifer Arcuri during his time as London Mayor.
The handful of Cabinet ministers attending conference were repeatedly quizzed about Johnson’s personal behaviour.
Chancellor Sajid Javid, who gave a set-piece speech promising billions of dollars in spending, and a one pound increase to the minimum wage from £9.50 ($17.29) forecast in 2023 to £10.50 in 2025, backed the Prime Minister, saying it was not his job to adjudicate complaints made against MPs.
“I’ve talked to the prime minister about that and first of all he couldn’t be clearer, absolutely clearer that they are completely untrue and I totally trust him on that.
“As to anything else about that, it’s not appropriate for me to discuss it, to get into it, because it’s just not right,” the Chancellor said.
Javid said personal allegations had been made against MPs “all the time” during his nine years in politics.
“Each time I’ve heard about them, whoever they’re about, I don’t get involved and don’t really comment on them because how would I know anything about these allegations, so it’s just inappropriate,” he said.
Speaking at an event on online harm, the Culture Secretary Nicky Morgan also backed her boss.
“Downing Street have been very, very clear about this that there is no truth to these allegations and I don’t have a comment to add,” Morgan said.
When pressed, the former Minister for Women said: “The prime minister has made very clear there is no truth to these allegations.”
Party Chairman James Cleverly was also questioned during an interview with POLITICO’s London Playbook.
“There have been things written about and flung at Boris the whole way through his career,” he said. “I judge him on his professional record in office.”
Tory conference has been plagued with no-shows by senior ministers who had expected to appear before the party faithful. Thanks to last week’s shock Supreme Court ruling Johnson’s prorogation of Parliament unlawful, they were instead required back in Westminster.
Michael Gove, who is in charge of the government’s No-Deal planning, returned to London instead of speaking at an event regarding the Commonwealth.
Similarly, Gavin Williamson, the Education Secretary did not attend a panel he was listed to speak on regarding Britain’s university sector.
Solicitor General Michael Ellis told a fringe event for The Policy Exchange think tank that the whips had placed him on “red standby” meaning that if he received a text message, he would have to be excused to “dematerialise” but added “I am not banking on that at all.”
Opposition parties said they would not grant the government an election for at least several weeks, to try and protect the county against a No Deal Brexit prompting Cleverly to make squawking noises to mimic a chicken.
Latika Bourke is a journalist for The Sydney Morning Herald and The Age, based in London.