Waitrose and Marks & Spencer have topped the Marine Conservation Society's Sustainable Supermarket League Table, which examines the UK supermarkets' commitment to sourcing fish from responsibly managed fisheries.

Tesco and Sainsbury's ranked third and fourth respectively, followed by Asda, Morrisons and the Co-op. Frozen food retailer Iceland ranked bottom of the list.

“MCS would like to see all supermarkets developing a comprehensive policy for imported farmed production as well as a greater focus on the sustainability of the feed used to grow farmed carnivorous fish both within the UK and elsewhere,” said the MSC's mariculture officer Dawn Purchase.