BRITISH PRIME MINISTER Boris Johnson may have had an “intimate relationship” with Jennifer Arcuri while London mayor, but will not face a criminal investigation over allegations he used his position to benefit the businesswoman, the police watchdog has said.

The Independent Office for Police Conduct (IOPC) said it “would have been wise” for Johnson to have declared their “close association” as a conflict of interest.

The prime minister welcomed the news that the “vexatious claims” that he used his City Hall role to assist and reward the American had not resulted in an investigation for misconduct in public office.

But the London Assembly pledged to resume its own probe into allegations Arcuri received thousands of pounds in public money and privileged access to three foreign trade trips led by the then-mayor.

IOPC director general Michael Lockwood said: “We found no evidence to indicate that Mr Johnson influenced the payment of any sponsorship monies to Ms Arcuri, or that he influenced or played an active part in securing her participation in trade missions.

“While there was no evidence that Mr Johnson influenced the payment of sponsorship monies or participation in trade missions, 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.”

The IOPC recommended that City Hall considers whether Johnson breached the code of conduct for failing to declare his relationship.

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

And, under the Nolan Principles of Public Life, “it would have been wise for Mr Johnson to have declared this as a conflict of interest”, a statement added.

A spokesman for the prime minister said the months-long scoping exercise “was a waste of police time”.

“We welcome the fact that this politically motivated complaint has been thrown out,” the spokesman added.

“Such vexatious claims of impropriety in office were untrue and unfounded.”

Neither Johnson nor Arcuri have ever denied that they were involved in an affair, during his time as mayor between 2008 and 2016.

The allegations were referred to the IOPC in September because the watchdog has a remit over the City Hall role, as head of the mayor’s office for policing and crime.

After the IOPC ruling, the London Assembly swiftly said it would resume its own investigation, which it paused when the watchdog launched its review.

Len Duvall, chairman of the Greater London Authority’s oversight committee, said: “The IOPC was looking specifically at whether he committed a criminal offence.

“That’s not our remit and their decision doesn’t have any real bearing on our investigation, which will focus on his conduct as mayor of London.

“Our investigation will consider whether Boris Johnson conducted himself in a way that’s expected from anyone in that position.”

The allegations surfaced in an investigation by the Sunday Times on September 22 last year, on the morning the PM was flying to New York to attend the United Nations General Assembly.

Initially he declined to deny any of the claims during sustained questioning on the RAF Voyager, but later broke his silence to insist “everything was done with complete propriety”.

Arcuri has said she had “every right” to go on the trade missions, describing herself as a “legitimate businesswoman”.

A government review in October said a separate £100,000 (€111,212) grant awarded to Hacker House, a company run by Arcuri, in 2018 was “appropriate”.

The newspaper investigation reported that Arcuri’s business received £10,000 (€11,121) in sponsorship from an organisation overseen by Johnson as mayor in 2013, and a further £15,000 (€16,681) was said to have come in 2014.