Lindsey Chapman tells the story of the Duke of Edinburgh’s lifelong work to raise awareness of ecological problems.

The programme includes archive of Prince Philip's many passionate speeches on the subject and his informed and characteristic bluntness in communicating the pressing nature of environmental concerns.

With Sir David Attenborough, environmental journalist Geoffrey Lean and archive of Sir Peter and Lady Philippa Scott - who founded the World Wildlife Fund (now the Worldwide Fund for Nature) and invited Prince Philip to be its first British president.

Broadcast as part of the BBC's obituary programmes for HRH The Prince Philip.