The government of London said it had referred Prime Minister Boris Johnson to Britain's police watchdog for potential investigation over allegations of misconduct involving a U.S. businesswoman while he was mayor of London.

The Greater London Authority (GLA) said on Friday it had referred a "conduct matter" concerning Johnson to the Independent Office for Police Conduct (IOPC) to determine whether there are grounds for a full investigation that could lead to criminal charges of misconduct in public office.

The matter has been referred to the police watchdog because 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 referral follows allegations that when Johnson was mayor, he failed to declare close personal links to tech entrepreneur Jennifer Arcuri, whose company Innotech, received 11,500 pounds (14,000 U.S. dollars) from London & Partners, the mayor's promotional agency, in public business funding and places on official trade trips.

In a letter to Johnson, the GLA said: "Subject to any explanation provided by you, these matters give rise to a suggestion that there has been a failure to safeguard the public purse and if so that amounts to a significant breach of public trust."

It said the action had been taken in accordance with the Police Reform and Social Responsibility Act 2011.

Johnson has vowed to take Britain out of the European Union by October 31. British opposition parties are discussing tabling a vote of no-confidence in Johnson as early as next week over his handling of Brexit.

(With input from Reuters)