The UK’s gambling regulator has announced a crackdown on online slot games, one of the most addictive forms of online betting, including bans on features that encourage people to place higher and more frequent stakes.

The measures outlined by the Gambling Commission on Tuesday come as discussions over a long-awaited overhaul of the UK’s legislation on the sector heat up. The government is consulting on a variety of possible curbs on the industry, including bans on sports sponsorship, advertising restrictions and checks on what customers can afford.

Features that will be banned under the new rules for online games include fast spin speeds and autoplay functions — which tend to encourage people to play more — and sounds or images that create the illusion that gamblers have won when the return was lower than the stake placed.

Operators must implement the controls by October 31, the commission said.

“The evidence shows that these features increase the risk of harm to customers,” said Neil McArthur, chief executive of the Gambling Commission, who added that the measures were “another important step in making gambling safer and where the evidence shows that there are other opportunities to do that we are determined to take them”.

Online slot games, which include basic fruit machine-style games during which punters bet on the outcome of a spin, are known to be some of the most addictive products offered by gambling companies. Commission figures show that the UK public spent £2.2bn on online slots in 2019.

Some 30m people in the UK gamble at least once a year, according to the commission. The average monthly spend per slots player is £67, compared with £36 for those playing casino products and £45 for real-life event betting, it said.

The regulator is under pressure to tighten controls over online gambling after an increase in the activity during lockdowns. Its own role as regulator is also under review as part of the overhaul of the UK’s 2005 Gambling Act.

Campaigners have been calling for statutory limits on the amount allowed to be staked online, similar to those on fixed-odds betting terminals in high-street betting shops, which were implemented in 2018.

“The elephant in the room is the maximum stake. It’s illogical to limit stakes on venue-based machines and not extend that online,” said Matt Zarb-Cousin, director of the lobby group Clean Up Gambling.

Brigid Simmonds, chair of the Betting and Gaming Council, which represents more than 90 per cent of the UK’s gambling companies, said that many of the new restrictions announced on Tuesday were already enshrined in the BGC’s own code of conduct.

She added that setting limits online was “almost impossible with the different multitudes of games that exist in the online space”.

The BGC has warned that putting strict caps on online gambling could drive punters to use unregulated offshore websites. According to research by the accountancy firm PwC, UK gamblers visit black market sites 27m times each year.

The PwC report has since been rejected by the Gambling Commission, which said in a letter to MPs last month that the data were “exaggerated” by “consultants paid for by the industry”.

The government is expected to present its proposals for reform of the gambling act in December this year with legislation expected in 2022.