Masterfoods, the makers of Mars and Snickers chocolate bars, is to stop marketing confectionery to children younger than 12 by the end of the year - the first time a major foodmaker has set such a high global age threshold for such products.

The measure reflects mounting concerns about the links between advertising and childhood obesity and follows moves by some public authorities to bring in tighter food regulations such as last year's ban on trans fats in New York's restaurants. The move by Masterfoods, one of the world's top 30 advertisers, is the biggest shift in marketing policy by a large food group since European officials threatened companies with regulation two years ago. It could drive other companies to adopt similar practices.