Boris Johnson has insisted he acted with “full propriety” when London Mayor as he came under more pressure with claims US model turned businesswoman Jennifer Arcuri told friends she had had a sexual relationship with him.

The Prime Minister has been referred to the police complaints body to assess whether he should face a criminal investigation for misconduct in public office over his links with Ms Arcuri, whose tech business received thousands of pounds of taxpayers’ money and who went on official trade missions abroad.

Asked if he had declared an interest relating to his links with Ms Arcuri when he was London Mayor, Mr Johnson replied: "Everything was done in accordance with the code...and everything was done with full propriety."

READ MORE: Boris Johnson seeks to focus attention away from damaging Arcuri claims towards £13bn hospital-building programme

Pressed again, he insisted: "There was no interest to declare...Let's be absolutely clear, I am very, very proud of everything that we did and certainly everything that I did as Mayor of London.

JohnsonBoris Johnson, accompanied by partner Carrie Symonds, arrives at the Conservative Party conference in Manchester (Stefan Rousseau/PA)

"I may say that the current Mayor of London could possibly spend more time investing in police officers than he is investing in press officers and peddling this kind of stuff," Mr Johnson told the BBC’s Andrew Marr programme.

The Greater London Authority[GLA] has said its monitoring officer recorded a "conduct matter" against the Conservative Party leader over allegations Ms Arcuri received favourable treatment because of her friendship with him while he was at City Hall.

The Independent Office for Police Conduct will now consider whether there are grounds to investigate the PM for the criminal offence of misconduct in public office.

The move has been greeted with fury in Downing St, which denounced the referral by the GLA, led by the current Mayor, Labour’s Sadiq Khan, as a "nakedly political put-up job" on the eve of the party conference.

Cabinet colleagues have rallied round Mr Johnson.

Matt Hancock, the Health Secretary, dismissed the claims surrounding the PM’s relationship with Ms Arcuri as a "squall".

Asked on Sky News's Sophy Ridge on Sunday programme if Mr Johnson had questions to answer, Mr Hancock replied: "No."

READ MORE: Call in Scotland Yard if Johnson fails to co-operate with 'conflict of interest' probes, says MP

He went on: "My understanding is that there is an investigation. Any monies involved went through proper due process. This was a long time ago. Of course, in politics, there are always squalls and there are always debates about individuals."

Theresa Villiers, the Environment Secretary, has insisted the Arcuri affair had been blown out of all proportion. “This seems to be pretty obviously a politically motivated complaint,” she claimed.

"The Prime Minister has been clear there is nothing to see here. I do feel this is a distraction and it is people seeking to use the complaints process in a highly political way," added the Cabinet Minister.

However, Jeremy Mr Corbyn has insisted a “wholly independent assessment” had looked at evidence of the payments made by the Mayor's office to one particular company and there were serious questions to answer.

“The job of the Prime Minister is to answer those questions," insisted the Labour leader