Boris Johnson has been challenged over his conduct with businesswoman Jennifer Arcuri during a live press conference from Downing Street.

The Prime Minister was asked if he had acted with “honesty and integrity” in line with the code of conduct for people in public life, following reports about his relationship with the American businesswoman.

Ms Arcuri made fresh allegations last month that she and Mr Johnson had a four-year romantic relationship when he was London mayor, in an interview with the Sunday Mirror.

During a live coronavirus briefing from Downing Street on Tuesday, HuffPost’s Paul Waugh asked Mr Johnson about his relationship with Ms Arcuri.

“On Greensill and lobbying, it’s sparked a lot of interest in whether the Nolan principles of public life have any teeth or relevance any more,” the journalist said.

“Do you agree with the Independent Office for Police Conduct (IOPC), which in its review of your links with Jennifer Arcuri concluded, and I quote, ‘it would have been wise for Mr Johnson to have declared this as a conflict of interest and a failure to do so could have constituted a breach of the Nolan principles’?

“Those principles include acting with honesty and integrity. Do you believe you acted with honesty and integrity in your relationship with Ms Arcuri, who claims you conducted your affair in your marital home?”

After answering a previous question on the expansion of Heathrow, the Prime Minister replied: “My answer to your second question is yes.”

The businesswoman’s links with Mr Johnson came under public scrutiny last year over allegations she received favourable treatment for her business ventures during his eight-year stint as mayor.

Mr Johnson avoided a criminal investigation after the police watchdog found no evidence he had influenced the payment of thousands of pounds of public money to Ms Arcuri or secured her participation in foreign trade trips he led.

However, the IOPC said it “would have been wise” for the former mayor to have declared their “close association” as a conflict of interest.

He still faces an investigation by the Greater London Authority’s (GLA) oversight committee into whether he conducted himself in a way that is expected of people in public office.

Mr Johnson has said his dealings with Ms Arcuri were “done with complete propriety” and previously welcomed the IOPC findings, as he criticised the “vexatious claims” against him.