Three gambling businesses owned by William Hill will pay a total of £19.2 million for “widespread and alarming” social responsibility and anti-money laundering failures, the Gambling Commission has announced.

The settlement is the largest in the Gambling Commission’s history.

WHG (International) Limited, which runs williamhill.com, will pay £12.5 million; Mr Green Limited, which runs mrgreen.com, will pay £3.7 million; and William Hill Organisation Limited, which operates 1,344 gambling premises across Britain, will pay £3 million.

This comes after two major operators of online gambling firm Kindred Group, 32Red and Platinum Gaming were slapped with a £7.1m fine for regulation failures.

Gambling Commission chief executive Andrew Rhodes said: “When we launched this investigation the failings we uncovered were so widespread and alarming serious consideration was given to licence suspension.

“However, because the operator immediately recognised their failings and worked with us to swiftly implement improvements, we instead opted for the largest enforcement payment in our history.”

Social responsibility failures at William Hill businesses included allowing one customer to open a new account and spend £23,000 in 20 minutes, allowing another to open an account and spend £18,000 in 24 hours, and a third able to spend £32,500 over two days – all without any checks.

Ineffective controls allowed 331 customers to gamble with WHG (International) Limited despite having self-excluded with Mr Green.

Anti-money laundering (AML) failures included allowing customers to deposit large amounts without carrying out appropriate checks – one customer was able to spend and lose £70,134 in a month, another to lose £38,000 in five weeks, and another to lose £36,000 in four days.

A spokesman for 888, which owns William Hill, said: “The settlement relates to the period when William Hill was under the previous ownership and management. After William Hill was acquired, the company quickly addressed the identified issues with the implementation of a rigorous action plan.

“The entire group shares the Gambling Commission’s commitment to improve compliance standards across the industry and we will continue to work collaboratively with the regulator and other stakeholders to achieve this.”

The Gambling Commission said all £19.2 million will be directed towards “socially responsible purposes” as part of a regulatory settlement.

The previous largest case was a £17 million action taken against Entain in August last year.

The William Hill settlement comes a week after the commission fined two operators owned by Kindred Group a combined £7.2 million and is the largest enforcement case taken on by the regulator.

Mr Rhodes said: “In the last 15 months we have taken unprecedented action against gambling operators, but we are now starting to see signs of improvement.

“There are indications that the industry is doing more to make gambling safer and reducing the possibility of criminal funds entering their businesses.”