Julian Metcalfe, the chain's co-founder, removed tuna and cucumber sandwiches, and banned endangered bluefin tuna from sushi boxes sold at Pret and its sister outlet, Itsu, Daily Telegraph reported.

The ban comes after watching the environmental documentary The End of the Line.

After watching the film, which is having its general release Monday, in line with World Ocean Day, Metcalfe contacted the film's producers and said: "Much as a result of your film, we took tuna out of Pret sushi entirely. No tuna in the box at all ....