Standards protecting children from irresponsible gambling ads have been strengthened to stop firms “playing at the margins” of rules, the regulator has announced.

The new standards drawn up by the Committees of Advertising Practice (CAP) prohibit online ads for gambling products being targeted at groups of people who are likely to be under 18 based on data about their online interests and browsing behaviour.

They also prohibit the use of sportspeople and celebrities or animated, film or TV characters who appear to be under 25 or are likely to be of particular appeal to the age group.

The standards add to existing guidance on the responsible targeting of ads to cover all media including social networks and other online platforms.

Gambling operators must use all tools available on a social network platform to prevent targeting their ads at under-18s and take particular care to avoid placing their ads on parts of websites of particular appeal to under-18s, such as a football club’s website pages dedicated to younger supporters.

Firms who use influencers to promote their products or brands should ensure that under-18s are not likely to comprise more than 25% of the audience.

The new standards follow a review of the evidence on advertising’s impact on under-18s and rulings by the Advertising Standards Authority.

The ASA’s rulings have included the banning of three Coral Interactive ads for featuring animated images of a rainbow, a pot of gold and a leprechaun, fish swimming in the ocean and a wizard, found likely to be of particular appeal to children.

A William Hill Vegas ad appearing within the app New MarioKart 8 Trick was banned for not being appropriately targeted away from children.

The gambling website m88.com advertised three games called Fairytale Legends Red Riding Hood, which showed an animated image of a wolf and a pixie, Fairytale Legends Hansel and Gretel, which showed an animated image of a forest, and Fairies Forest, which showed an animated image of a fairy in a forest, all of which were banned for appealing to children.

CAP said that while the advertising rules did not need to change, the new standards would strengthen how they apply in practice.

They come into force on April 1.

CAP director Shahriar Coupal said: “Playing at the margins of regulatory compliance is a gamble at the best of times, but for gambling advertisers it’s particularly ill-advised, especially when the welfare of children is at stake.

“Our new standards respond to the latest evidence and lessons from ASA rulings, and require that greater care is taken in the placement and content of gambling ads to ensure they are not inadvertently targeted at under-18s.”