Illegal imported sweets that contain banned additives linked to cancer and behavioural problems are “flooding UK high streets”, councils have said.

The warning first came from the Chartered Trading Standards Institute (CTSI), which said that demand for American confectionery was being driven by influencers on social media platforms.

Colourful drinks and sweets being showcased on platforms such as TikTok had led to an increase in demand among children and teenagers, regulators have said.

Viral videos show users demonstrating their “candy hauls”, and taste testing imported products.

Capitalising on the demand, high street shops and smaller convenience stores have begun stocking the products, with “millions” being imported into the UK.

In December, Staffordshire county council said that during a pilot project funded by the Food Standards Agency, it had seized 3,378 items valued at £8,500 from shops.

This week, Manchester city council said it was taking the issue “very seriously” and that its environmental health team had been seizing illegal products from shops. The local authority urged residents not to buy the products for children.

“We’re working hard to protect consumers by removing these products from local shops and educating shopkeepers about the dangers,” a spokesperson said. “If you see a product with one of the banned ingredients, please report it.”

The banned additives have been linked to various health issues, including hyperactivity, cancer, kidney and other organ damage, and reduced immune function.

Banned ingredients include brominated vegetable oil (BVO), mineral oil, bleached flour, and additives including Sunset yellow FCF, Allura red, and Tartrazine.

Imported foods and drinks which have been found to contain banned additives include, but are not limited to, Jolly Rancher Hard Candy, Fanta Pineapple, Swedish Fish, Sunny D, Prime Hydration, Cheetos Crunchy.

However, some of the brands in which prohibited additives have been found also have products intended for the UK market which comply with legislation, and customers have been urged to check labels for any banned ingredients.

Products labelled with US weight measurements, including ounces and fluid ounces, are likely to be imports.

“The UK prides itself on high food standards but this very much relies on trading standards ensuring that what is on sale complies with the law,” the CTSI chief executive, John Herriman, said.

“Trading standards work extremely hard to protect the public by removing dangerous products from sale, but the popularity of these items is being increased by videos on social media platforms, such as TikTok.

“The increase in demand means importers are sending these through our ports and borders in the millions, and these are then being widely distributed and ending up in retail stores and in the hands of children.”

He urged people putting the products on the market, including suppliers and retailers, to take their responsibilities seriously and remove any from sale that contained unauthorised ingredients.

“We also urge parents to be aware,” he said. “If shop owners are unsure of what items are safe to sell, they should contact their local trading standards service for support and advice.”