Matt Baker and Margherita Taylor commemorate 200 years since the birth of the railways with a journey on the Watercress Line in Alresford, Hampshire. They explore how the advent of steam engines connected rural England to cities, providing farmers with the vital link needed to distribute their fresh produce across the UK. Matt visits watercress growers gearing up for this year’s crop and helps prepare their gravel beds ready for seeding, and he learns about the role of river invertebrates in modern farming practices. Margherita meets the people keeping the heritage line alive, helps volunteers clear a disused railway to create a new wildlife corridor, and she meets a local who has set up a community farm shop which sits in the middle of what put this area on the map – watercress beds! Meanwhile, Tom Heap investigates the system designed to protect farmers selling to big supermarkets and asks how well it’s really working.