Three former Toronto mayors are urging Rob Ford and his council counterparts to oppose a casino in the city’s core, warning that the revenues generated from the facilities often fall short of what was promised.

A letter signed by former mayors David Crombie, John Sewell and Art Eggleton warns of increased crime, traffic congestion and social welfare costs that often accompany casinos.

“Beware of the sales pitch,” reads the letter. “The numbers don’t always add up…Revenues can be inflated and costs such as police services and traffic congestion underestimated.”

A proposal by MGM, one of the world’s largest gaming companies, claims a casino resort project in Toronto’s downtown will attract one million tourists yearly, who would spend an estimated $1 billion in spin-off industries.

MGM Resorts CEO Jim Murren had pitched a casino plan earlier this month that includes a partnership with Cirque du Soleil and high-end dining. He also said that the gaming facility will create thousands of “good-paying jobs.”

However, in their letter, the ex-Toronto mayors pointed to a U.S. study that showed for every $1 in benefits from a casino, there is a cost of at least $3 to the city for additional policing, and larger social welfare costs.

“And how will local businesses in and around the Casino be affected?” the mayors ask. “Casinos want to keep you in the building, not roaming to outside restaurants and other establishments in the community.”

The mayors note that governments shouldn’t use gambling revenues as a means of balancing their budgets.

“Toronto is not about to become another Las Vegas, a tourist gambling destination. And we wouldn’t want it to,” the letter reads.

A report released by the city manager in November said Toronto could see as much as $27 million generated annually from a gaming complex in property taxes alone. A standalone casino could generate up to $10 million.

The city recent wrapped up a series of public meetings on the casino. Feedback collected during the town halls and through online surveys will be complied into a report to be presented to the Mayor’s executive committee in March.

City council is expected to vote on the casino question in April.