Mars has bowed to consumer pressure and backtracked on its decision to use whey containing animal rennet in its chocolate bars.
The manufacturer had altered the ingredients used in a number of its top-selling bars, including Mars, Bounty, Snickers and Twix, making them unsuitable for vegetarians.
The action prompted wide-spread outrage from retailers, consumers, vegetarian groups and MPs last week.
"It became very clear, very quickly that we had made a mistake, for which I am sorry," said Fiona Dawson, managing director of Mars UK. "There are three million vegetarians in the UK and not only did we disappoint them, we upset a lot of the consumers."