The Betting and Gaming Council, the industry lobby group, said it had given £170m to fund gambling harm services over the past four years on a voluntary basis.

However, the government said that, under the current system, not all gambling companies contributed equally, “with some operators paying as little as £1 a year towards research, prevention and treatment”.

Grainne Hurst, chief executive of the Betting and Gaming Council, said the body supported the government’s proposals.

However she added: “The tone of this announcement suggests government is at risk of losing perspective of these facts, while simply dancing to the tune of anti-gambling prohibitionists, which serves no one.”

DCMS said its mandatory levy would raise £100m for “the research, prevention and treatment of gambling harms”.

Half of the money raised is to go on directly NHS care, 30% will be spent on public health campaigns and other prevention measures, and the remaining 20% will be spent on research, the government said.

Mark Weiss, deputy chief executive of GamCare, welcomed the government’s proposals.

“Having witnessed a steep rise in our helpline callers citing difficulties with online slots, GamCare further welcomes the introduction of new youth-focussed stake limits – an important step in preventing future harm,” he said.

DCMS said the levy could apply to anywhere between 0.1% and 1.1% of a firm’s gross gambling yield – a standard measure of earnings in the industry – “depending on the sector”.

The proposals are a response to a consultation run by the previous Conservative government between October 2023 and January 2024.