Tesco has denied selling unethically caught tuna in its Oxford stores.
Environment campaigners said they found Tesco stores in the city selling canned tuna singled out for criticism by Greenpeace and in Hugh Fearnley-Whittingstall’s Fish Fight TV programme.
Campaigners say the tuna is caught using methods that can kill sharks, rays and turtles.
Tesco spokesman Alasdair Gee dismissed the claims saying: “We moved much faster than many of our competitors to make sure our own-brand tuna is 100 per cent pole and line.
“We have also promised to use sustainable tuna in other products like pastas, sandwiches and salads.”