Marie Rose sauce (known in some areas as cocktail sauce or seafood sauce) is a British condiment often made from a blend of tomatoes, mayonnaise, Worcestershire sauce, lemon juice and black pepper. A simpler version can be made by merely mixing tomato ketchup with mayonnaise. The sauce was popularised in the 1960s by Fanny Cradock, a British cook.
It is often used to accompany seafood, prawns in particular.