William Hill slashes value of Tom Waterhouse-led Australian business

Its Australian business, whose chief executive is high-profile bookmaker Mr Waterhouse, has been placed under a "strategic review" and is now up for sale. Industry sources confirmed multiple bookmakers had done due diligence on William Hill Australia in recent weeks, and said a deal could be sealed imminently.

Unlike many of Australia's other prominent online bookmakers, who had agreed to the credit-betting ban that was contained in a suite of new responsible-gambling laws, Mr Waterhouse's William Hill Australia has been fiercely resistant.

Fairfax Media last month revealed the company's biggest credit-betting customer to be celebrity real-estate identity John McGrath, who has been incurring average gambling losses of $10 million a year and owed a $16.2 million gambling debt to William Hill.

Mr McGrath this month confirmed he had a credit-betting account with a bookmaker. But the millionaire said it was no threat to his business or his wealth.

"The account is well within my means in the context of my net wealth," he said.

Mr McGrath has a 26 per cent shareholding in the eponymous real estate company worth about $17 million as well as a significant stake in REA Group, which is worth about $10 million and millions of dollars' worth of other assets.

Announcing its yearly results on Friday, William Hill revealed the £238 million ($424 million) write-down against its Australian business, which accounts for 7 per cent of William Hill's overall group revenue. The write-down pushed William Hill to a pre-tax loss of £74.6 million ($133 million).

William Hill said the credit ban would take a heavy toll on its operations in Australia, while profitability was set to be worsened with the introduction of so-called "point-of-consumption" taxes sweeping the country.

South Australia, Western Australia and Queensland have so far moved to introduce 15 per cent taxes on digital gambling companies based on where bets are placed, as opposed to where the company is located.

Australia's two biggest gambling jurisdictions, Victoria and New South Wales, are expected to announce similar taxes soon.

"While we remain one of the few profitable companies in the market, that profitability would be significantly impacted if, as is anticipated, further states introduce an additional 15 per cent point-of-consumption tax in the coming months and years," the company said.

William Hill spent an estimated $700 million buying into the ultra-competitive Australian online gambling market in 2012 and 2013, acquiring tomwaterhouse.com, Sportingbet and Centrebet.

While unveiling William Hill's results last week, chief executive Philip Bowcock reportedly said taxes had been in the high single digits when the company had first moved into Australia.

"If you go back in time to 2013 when we acquired the business, Australia was a different place," he said.

William Hill's Australian spokesman on Sunday referred questions to its UK office.