Tesco has been slammed for selling fruit that is not suitable for people following a vegan diet.

Britain’s biggest supermarket is looking for alternatives after criticism over the wax applied to some of its fruit after harvesting.

Shellac, a resin from the female lac bugs found on trees in the forests of India and Thailand means the zest from the peel of oranges are unsuitable for vegans.

Tesco confirmed that its oranges are labelled non-vegan because of this however the supermarket has faced criticism for “letting its standards slide”.

The growing popularity of a vegan diet - where people don't eat any produce that comes from animals - means the supermarket is now working on developing an alternative method.

Although some shoppers have slammed the retailer for being too slow to act, reports The Telegraph.

One social media user said: It's not something I have ever thought about. I assumed fruit was always vegan."

Another added: "Most (supermarkets) have taken action. Clearly Tesco has let its standards slide."

It comes after Pizza Express faced similar criticism for using the same wax on its lemons.

Author Jack Monroe questioned why a glass of Coca Cola was only vegan if "served without lemon".

The resturant replied: "The wax on waxed lemons contain shellac, which is derived from insects and therefore strictly not vegan."