Marks & Spencer and Waitrose have topped a league table for the sustainable sourcing of seafood published by the Marine Conservation Society.

The retailers came joint first with a score of 83%.

Tesco came third with 53%, while Sainsbury's slipped back to fourth place this year on 50%. Asda's activity in moving to Marine Stewardship Council-accredited fish lines seems to have paid off, as it rose two places to fifth.

Morrisons came sixth, The Co-operative Group seventh and Iceland eighth.

Somerfield, which scored poorly last year, failed to respond to this year's survey.