The government is set to impose new limits of as little as £2 a spin for online slot machines, the Guardian understands, in a move that could cost casino companies hundreds of millions of pounds. Ministers have been consulting on imposing a maximum stake for the digital casino-style games since publishing a white paper on gambling reform last year. The Guardian understands that the new limit, which will be announced on Friday, will be £2 for under-25s, similar to the limit imposed by the government on fixed-odds betting terminals (FOBTs) in 2019. There will be a higher limit of £5 a spin for anyone over that age. At the moment, there is in effect no limit on the amount that gamblers can stake on the games, which make more than £3bn a year from players and carry a higher rate of addiction than other products, such as betting on football. Some of the larger operators do impose limits voluntarily. Gambling campaigners and industry sources told the Guardian that they were expecting the Department for Digital, Culture, Media and Sport (DCMS) to reveal more details, including when the restrictions will come into force, on Friday. The DCMS declined to comment. The restriction could cost the UK gambling industry hundreds of millions of pounds in revenues. When the government began its consultation on what limits to impose, it suggested a range of between £2 and £15. The white paper, published in April 2023, estimated that setting the limit at £8.50, the mid-point of the suggested range, would cost the industry up to £185m. But imposing a limit of £5, or £2 for younger players, is likely to cause the cost to online casino companies to soar beyond that level. An industry source said setting two-stake limits was also likely to add costs for operators. Campaigners concerned about the dangers of addiction welcomed the measure but said it did not go far enough. “I am pleased that the government has seen sense and opted for a £2 limit for people under 25,” said the Labour MP Carolyn Harris, who chairs a cross-party group of MPs examining gambling-related harm. “There is, however, clear evidence that a £2 limit should be in place for everyone to prevent harm. The government has sided with the industry and should rethink.” Liz Ritchie, who co-founded the charity Gambling With Lives after her son Jack took his own life following a gambling addiction, said: “The gambling industry may present this as harm to their profit margin but the real harm is to the millions trying to cope with addiction caused by toxic gambling products, and the terrible suffering of families bereaved by gambling suicide. “The government has lost another opportunity to stop the harm caused by high stake sizes, and the truth is that many more people will die.” Online casinos are the largest and fastest-growing segment of the gambling industry, accounting for £4bn of the sector’s £11bn in revenues last year, excluding the national lottery. Of that £4bn, slots account for £3.2bn, according to the latest statistics from the Gambling Commission, for the year to March 2023. Alongside new limits on slot machine stakes, the industry regulator, the Gambling Commission, is consulting on affordability checks that gamblers could be forced to pass if they rack up losses. New polling figures released on Thursday show that the majority of people support such checks, despite opposition from sections of the horse racing industry. Research by pollsters at Ipsos, commissioned by the UK’s leading gambling charity GambleAware, found broad support for both light-touch and enhanced checks, both among gamblers and those who have not placed a bet in the past 12 months. While about a third of people said they believed such checks would be an intrusion on privacy, far fewer said they would actually oppose them. The government set out its proposals for reform of gambling regulation in the white paper last year, including a mandatory levy to fund addiction treatment, education and research, as well as the affordability checks and the new online slot machine limits. It asked the Gambling Commission to consult on plans for two possible levels of checks on gamblers, depending on their losses and age. The GambleAware survey found net support for both types of check.