“Some of the UK’s best-selling chocolate bars, such as Mars and Twix, will no longer be suitable for vegetarians.
Also affecting brands such as Snickers and Maltesers, owner Masterfoods said it had started to use animal product rennet to make its chocolate products.
Masterfoods said the change was due to it switching the sourcing of its ingredients and the admission was a “principled decision” on its part.”
I think the Vegetarian Society got it right:
“At a time when more and more consumers are concerned about the provenance of their food, Masterfoods’ decision to use non-vegetarian whey is a backward step”
BBC