John West accused of breaking tuna pledge
The UK's biggest tuna brand, John West, has been accused of catching just 2% of its fish using pole-and-line, despite making a pledge that 100% of its tuna would be sustainable by 2016.
Greenpeace said 98% of the firm's tuna was caught using methods that killed other animals, including sea turtles and sharks.
But John West said pole-and-line supply had reduced significantly.
It added it was "fully committed" to protecting the marine environment.
The latest Greenpeace league table for tuna sold by supermarkets and companies puts John West in last place, because of its use of "fish aggregation devices" that kill other species in the sea.
Waitrose, Marks & Spencer and Sainsbury's were in the top three spots on the table, while Tesco had made great progress to jump up to fourth place, Greenpeace said.
But John West said there was "no longer enough pole-and-line tuna available to meet global demand".
"Our total pole-and-line supply is considerably higher than the Greenpeace league table suggests; much of this is supplied to retailers for their private labels to help them achieve their stretching sustainability targets," it said.
It added that it defined sustainably sourced fish as "not being endangered or threatened, caught by well-managed fisheries with scientifically based quotas, via responsible fishing methods, and traceable from catch to consumer".
By this definition, it was already meeting its sustainability targets, it said.