Websites Kindernauts and Magic Kinder broke online rules on advertising foods high in fat, sugar and salt to children, a watchdog has ruled.

Campaigners have welcomed the judgement on the websites, an app and a YouTube channel that were promoting Kinder chocolate and toys.

One site promised "fun activities" - placed next to the Kinder chocolate brand.

In January Newsnight highlighted a series of advert come games on the site.

The chief executive of the Advertising Standards Authority (ASA), Guy Parker, told the programme: "You should not - if you're a company with a brand that's high in fat, salt or sugar - be producing 'advergames' that target children."

Media playback is unsupported on your device Media caption Kinder: Company bends sugar rules as games show real toys

The games included skateboard racing and a hunt for a golden egg. The content included characters you would find inside a Kinder Surprise and Kinder branding.

Kinder told Newsnight in January: "The games section of the Magic Kinder website has been designed to provide a positive play and learning experience between parents and children."

Kinder has now been rebuked by the advertising watchdog for a string of online games and marketing material aimed at children.

On Wednesday, the ASA ruled that the adverts "must not appear again".

Image copyright Kinder Image caption Stills from the Kinder games show characters used in products for children

A spokesperson for Kinder's parent company Fererro told Newsnight that a decision had been made to temporarily suspend the relevant websites.

They said: "We believe this highlights the need for further guidance and consultation on marketing across the UK industry."

Aim to 'halve obesity'

Barbara Crowther from the Children's Food Campaign, which lodged the complaint, said the ruling would make companies think carefully about the use of child-friendly cartoons.

"Kinder websites and advergames had created sub-brands which heavily featured the toys and characters associated with Kinder Surprise chocolate products," she said.

Newsnight's January investigation into advertising also looked at Coco Pops Granola - which has been advertised on children's television.

Last month Kellogg's was told by the ASA to remove Coco Pops Granola adverts from children's advertising.

The authority ruled that although the product was not a high fat, sugar or salt one, because the Coco Pops branding was synonymous with Coco Pops original cereal and with the Coco Pops range, the ad had effectively promoted the range.

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