Wandle wander: a walk along my south London chalk stream

England is home to 85% of these often-pristine rivers – some running through our suburbs – but we may lose chalk streams unless we start protecting them nowThe day before lockdown 2 in England, I’m walking alongside a stream on a frost-crisp morning, making the most of the winter sunshine before my movements are restricted for another month. To one side of the stream is a Sainsbury’s superstore that appears to be under siege, a queue already snaking around the block; to t