Why does the River Wye turn green?

Our correspondent investigates the health of 'the nation's favourite river', flowing through Wales, Herefordshire and Gloucestershire, from Plynlimon to Chepstow, passing through Hay-on-Wye, Hereford, Ross-on-Wye, Symonds Yat and Monmouth.

BBC’s Environment Correspondent Jonah Fisher speaks to James Wright from The Whittern farm at Lyonshall, citizen scientists in Presteigne and Charles Watson from River Action.

The Environment Agency has been in court – accused by campaigners of failing to protect the River Wye from pollution. The charity, River Action, says the government agency has failed to enforce the laws designed to keep the water clean and healthy. The judicial review is being held over two days at Cardiff Civil Court, with more details on the BBC News website.