M&S Brown Crab & Prawn Cocktail Atlantic prawns with a rich and creamy brown crab Marie Rose sauce. Our M&S seafood products have been sourced from fisheries and fish farms in a way that minimises their ethical and environment impact, while guaranteeing you the highest quality, delicious seafood you’d expect from M&S. Responsibly Sourced, Atlantic prawns with a rich and creamy crab Marie Rose sauce, Ready to Eat