A chocolate maker has been urged not to use animal rennet in its products.

Darwen and Rossendale MP Janet Anderson submitted an Early Day Motion in the House of Commons asking Masterfoods Ltd to keep bars such as Mars, Maltesers and Snickers free of the animal product as vegetarians will no longer be able to enjoy them.

Rennet is a natural complex of enzymes produced in the stomach to digest the mother's milk.

Masterfoods revealed this week that it had switched the sourcing of its ingredients and animal rennet was now being used.

The motion, signed by 36 MPs so far, says: "This house. . .considers this to be a regressive step in contrast to other producers who are removing animal products from their ingredients.