Advertising for products high in fat, salt and sugar (HFSS) is being shown during 12 of the 20 television programmes most watched by children, Which? has claimed.

The industry is currently banned from advertising HFSS products during programmes predominantly watched by children but a survey by the consumer watchdog found ads for products such as Mars, McDonalds, Milky Way and Twix were shown during programmes including The X Factor, Ant and Dec's Saturday Night Takeaway and Coronation Street.

“This research shows that unhealthy foods are being advertised during the programmes with the highest number of child viewers, such as The X Factor,” said Which? food campaigner Miranda Watson. “The only way to shield children from TV ads for unhealthy foods is a 9pm watershed.”