British Prime Minister Boris Johnson will not face criminal action following allegations of misconduct over his relationship with a US tech entrepreneur but he might have had an intimate relationship with her, the police watchdog said on Thursday.

The Independent Office for Police Conduct (IOPC) launched an investigation last September following a newspaper report that Mr Johnson, when mayor of London, had failed to disclose his personal links to Jennifer Arcuri, who received thousands of pounds in public funding and places on official trade trips.

Mr Johnson denied any wrongdoing, saying everything was done with full propriety and that there was no interest to declare.

The IOPC’s Director General Michael Lockwood said there was no evidence to indicate Mr Johnson influenced any payments to Ms Arcuri or influenced her participation in trade missions.

IOPC confirms no criminal investigation into Boris Johnson MP

Read our statement and download the report 👇https://t.co/xpsZjaFtQp pic.twitter.com/MBSpxRuOhd

— Independent Office for Police Conduct (IOPC) (@policeconduct) May 21, 2020

But Mr Lockwood said “there was evidence to suggest that those officers making decisions about sponsorship monies and attendance on trade missions thought that there was a close relationship between Mr Johnson and Ms Arcuri, and this influenced their decision making”.

Mr Johnson’s spokesman welcomed the fact that “this politically motivated complaint had been thrown out”, saying it was a waste of police time.

“Such vexatious claims of impropriety in office were untrue and unfounded,” the spokesman said.

The matter was referred to the watchdog because Mr Johnson was head of the Mayor’s Office for Policing and Crime, a role equivalent to a police commissioner, during his 2008-2016 term as mayor.

The IOPC said it “would have been wise” for Mr Johnson to have declared his “close association” with Jennifer Arcuri as a conflict of interest. Photo: PA Wire

The Greater London Authority said it had alerted the IOPC because Innotech, Ms Arcuri’s then company, had received £11,500 ($21,286) from London & Partners, the mayor’s promotional agency, for two events in 2013 and 2014.

She attended a trade mission to Singapore and Malaysia in 2014 through Playbox, one of her companies, even though an initial application through Innotech had been declined.

Last October, the government’s Internal Audit Agency ruled a decision to award a £100,000 grant to a company run by Ms Arcuri was appropriate.

Ms Arcuri gave a number of TV interviews after the allegations came to light, saying she and Mr Johnson had enjoyed a “very special relationship”, having bonded over classical literature, but said he had never shown her any favouritism.

She repeatedly refused to say whether she had had an affair with Mr Johnson but said he had cast her aside like “some gremlin” after the reports surfaced.

“Our review established there was a close association between Mr Johnson and Ms Arcuri and there may have been an intimate relationship,” the IOPC said.

It said it would have been wise for Mr Johnson to have declared this as a conflict of interest and might be a breach of the GLA’s Code of Conduct.

The London Assembly said it would continue its investigation into Mr Johnson’s conduct.

“My message to the prime minister is that this issue isn’t going away just yet,” Assembly member Len Duvall said.

-AAP