(CNN) British Prime Minister Boris Johnson has been referred to a police watchdog over his alleged relationship with an American businesswoman when he was mayor of London.

On Friday, the Greater London Authority (GLA) said in a statement that it has asked the Independent Office for Police Conduct to assess whether it is necessary to investigate Johnson for the criminal offense of misconduct in public office.

"Allegations have been brought to the attention of the Monitoring Officer that Boris Johnson maintained a friendship with Jennifer Arcuri and as a result of that friendship allowed Ms Arcuri to participate in trade missions and receive sponsorship monies in circumstances when she and her companies could not have expected otherwise to receive those benefits," the monitoring office of the GLA said in a statement.

Arcuri and her company have not responded to CNN's request for comment. She told the Sunday Times, "any grants received and any trade mission I joined were purely in respect of my role as a legitimate businesswoman."

Downing Street declined to comment to CNN on the allegations, but Johnson said in BBC interview that everything was done "entirely in the proper way."

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