Following claims that traces of meat were found in supermarket food products sold as "vegetarian" or "vegan", the Food Standards Authority (FSA) has said it is launching an investigation.
According to its report, two of the 10 products were found to contain small quantities of meat.
Traces of turkey were allegedly found in Tesco's BBQ Butternut Mac, a vegan product that forms part of the chain's Wicked Kitchen range. Meanwhile, Sainsbury's own-brand Meat-Free Meatballs, a vegetarian product, were allegedly found to contain traces of pork.
An FSA spokeswoman told Sky News: "Our priority is to ensure consumers can be confident that the food they eat is safe and is what it says it is. We are investigating the circumstances surrounding these alleged incidents and any resulting action will depend upon the evidence found."
Both supermarkets have insisted that their own checks have uncovered no traces of meat in the products called into question.
A Sainsbury's representative told the press: "These products are produced at a meat-free factory. Sainsbury's and the Vegetarian Society also carry out regular checks and no issues have been found. We are concerned by these findings however and are carrying out a comprehensive investigation alongside our supplier."
A Tesco representative said: "We take the quality and integrity of our products extremely seriously and understand that our vegan and vegetarian products should be exactly that. Our initial DNA tests have found no traces of animal DNA in the BBQ Butternut Mac product available in stores today.
"We would urge the Telegraph to share full details of their testing, including the lab used, as we continue to investigate."