PHOTO: Real estate agent John McGrath is said to have a large debt with William Hill. Photo: Louise Kennerley.

It has been one of the worst kept secrets in the gambling world: prominent real estate figure John McGrath has a $16.2 million gambling debt to the Tom Waterhouse- run betting company William Hill Australia.

“This would be the biggest debt ever in gambling history by a single person to a single company in Australia,” said one industry insider.

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