Marmite, Plastic, Custard

Jimmy finds out that shellfish consumed by millions have been feeding on plastic discarded in the sea, with shocking global implications. Kate finds out whether the makers of Marmite can really predict whether people will love or hate their distinctive yeast-based spread, as claimed in their latest TV advert, and Matt aims to solve the age-old mystery of how to smoothly extract ketchup from a bottle - by running across a pond of custard.