Boris Johnson has avoided a criminal investigation into his relationship with the US businesswoman Jennifer Arcuri while he was mayor of London. But he will face a further investigation into his conduct when he was mayor, after the Independent Office for Police Conduct (IOPC) found evidence that officials were influenced by the close relationship between the pair. Johnson was formally referred to the watchdog in September because he was the head of the mayor’s office for policing and crime at a time when Arcuri received public money and access to trade trips led by him when he was mayor. Arcuri was awarded thousands of pounds in public money, including £11,500 by the mayor’s promotional agency London & Partners (L&P). Johnson’s office also intervened to give her a place on trade missions to New York and Tel Aviv with Johnson, after she was initially turned down because she failed to meet the criteria. The IOPC concluded that no criminal inquiry was required following an eight-month scoping exercise into whether Johnson should be investigated for misconduct in public office over his friendship with Arcuri. But its 112-page report did say Johnson should have declared an interest in Arcuri. And that his failure to do so could have amounted to a breach of the London assembly’s code of conduct. Its 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.” But he added: “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.” Decisions about whether Arcuri should attend the trade mission were discussed with an official in Johnson’s office referred to in the report only as ‘Mr I’ understood to be Johnson’s director of communications Will Walden. The official told the inquiry he was aware of rumours about the closeness Johnson to Arcuri. But he said: “you don’t ask your boss if they’re having an affair.” Mr I also said: “It was raised with me that she didn’t qualify to come [on a trade trip to New York], which was something that I probably should have asked her questions [on] but I never did.” The IOPC noted that Johnson has never publicly accepted he had an affair with Arcuri, but has not denied it either. Arcuri refused to discuss her private life with IOPC but she told them there were “always whispers about me from day one.” The IOPC recommended that the Greater London Authority conduct a review of L&P policies and processes around the payment of sponsorship money. The London assembly said it would resume its investigation after the decision, with Len Duvall, the Greater London Authority’s oversight committee chair, saying: “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.” A spokesman for the prime minister said: “We welcome the fact that this politically motivated complaint has been thrown out. Such vexatious claims of impropriety in office were untrue and unfounded.” Referring to a report that cleared the culture department of any wrongdoing in awarding Arcuri’s company Hacker House an £100,000 grant last year, he added: “An independent review by the government internal audit agency similarly showed the claims made by the Labour party were false. “This was not a policing matter, and we consider this was a waste of police time.” Arcuri has said that she was given no favours by Johnson, but she conceded that the then mayor should have declared their friendship. The IOPC repeatedly insisted that it had been under no pressure from the government over the decision, which was expected before last December’s general election, or over its timing. The IOPC has a duty to investigate any alleged criminal offence committed by a figure in charge of policing, whether or not they are still in office. The IOPC’s view that prime minister does not have a criminal case to answer will come as huge relief to Downing Street. But now the City Hall watchdog will take up scrutiny of the matter. The oversight committee had put its inquiry on hold at the request of the IOPC. Duvall added: “Everyone who holds public office, whether you’re the mayor of London, or indeed the prime minister, is expected to adhere to the principles of public life - including integrity, selflessness, openness and honesty, to name a few. “Our investigation will consider whether Johnson conducted himself in a way that’s expected from anyone in that position. It’s important we get those answers, because Londoners deserve to have their politicians held accountable. “The oversight committee will take into account the current emergency when looking at the timetable for the investigation.” The committee has threatened to use its power to summon Johnson to answer questions as it did over the “garden bridge” fiasco. The oversight committee works to a lower standard of proof than the “beyond reasonable doubt” threshold required for criminal action, but cannot apply any sanction other than a public report.