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 big foodmaker has set such a high global age limit for products.

The move, which follows mounting concerns about the links between advertising and childhood obesity, is the biggest shift in marketing policy by a large food group since European officials threatened companies with regulation two years ago. It may prompt other companies to follow suit.