London's City Hall will formally refer a sacked adviser to Boris Johnson to police today over allegations he misused a corporate credit card.
Ian Clement resigned as Mr Johnson's deputy major for external relations on Monday after "discrepancies" were discovered in his use of the card.
Three Conservative council leaders have denied they dined with Mr Clement on occasions when he listed them as his guests in his expenses claims.
The head of financial services for the Greater London Authority (GLA) contacted Scotland Yard's Economic and Specialist Crime unit about the case yesterday, members of the London Assembly heard.
Martin Clarke, the GLA's executive director of resources, told a meeting at City Hall: "An initial meeting has been held.
"A formal referral to the police will be held today. It will then be the police's decision whether to take that forward."
Concerns about Mr Clement's use of his corporate credit card were first raised last August, the assembly's business management and administration committee heard.
Mr Johnson ordered him to give up the card after learning that he had used it to upgrade himself to business class on a flight to the Beijing Olympics.
But the former deputy mayor kept the card, despite receiving further warnings about his spending from November onwards.
Mr Clement used it to pay for meals including a £700 dinner in New York, and to buy more than £200-worth of groceries and a £535.49 audio system for his Jaguar.
He also withdrew cash on the card - incurring fees and interest payments - even after being told not to.
Mr Clement, the former leader of Bexley Council in south east London, finally had the card confiscated last week for using it to buy £2,300-worth of personal items in a breach of GLA regulations.
An initial internal GLA investigation found he repaid all the money at the earliest opportunity and made no personal gain.
But new discrepancies came to light, and he was forced to resign from his £127,000-a-year post on Monday.
Sir Simon Milton, London's deputy mayor for policy and planning, said Mr Clement offered to repay any money he should not have claimed.
He went on to say that he was "surprised" by the large amounts claimed by the former deputy mayor for entertaining, noting they were higher than those of Mr Johnson's other senior advisers.
He said: "There was an imbalance in that it was quite clear that most of the people who were being entertained were Conservative politicians.
"If he had been doing his job properly, there would have been a much greater balance across political parties."
Len Duvall, leader of the Labour group on the London Assembly, observed that some of Mr Clement's claims for lunch were contradicted by receipts showing the meal happened in the evening.
Mr Clarke said there were only seven corporate credit cards issued to people in the GLA, and the mayor does not have one.
The expenses claims made by Mr Clement which are under the spotlight include:
* £32.50 for lunch at Pizza Express in Barnet on October 31 last year with Michael Rye, leader of Enfield Council in north London.
Mr Rye says he saw Mr Clement in Enfield that day but did not dine with him;
* £72.50 for a meal with Mike Freer, the leader of Barnet Council in north London, at the Blue Olive Greek restaurant in Barnet on November 5.
Mr Freer insists he was attending a funeral in Inverness on that day;
* £51.70 for dinner at the New Mayflower Chinese restaurant in London's West End with Merrick Cockell, leader of the Royal Borough of Kensington and Chelsea, on November 6.
Mr Cockell says he was not there. He attended an awards ceremony before going to an event organised by the Local Government Chronicle.
Mr Johnson will be invited to address the business management and administration committee at a future date.