Matt Baker and Ellie Harrison are in the Lee Valley, the green lung of London. It has provided fun and fresh air for city dwellers for more than four decades but, as Ellie discovers, there is an incredible array of wildlife here too. She takes to the water to see what is being done to clean up its chalk streams and she discovers why common terns are making the Lee Valley home. As well as being its lungs, it is London's larder too, as Matt finds out when he meets the Sicilian siblings who have turned salad growing into a thriving family business.
