David Attenborough has described the human impact on the deep ocean floor as “unspeakably awful” in a conversation with Prince William to mark the launch of the veteran broadcaster’s latest documentary.

The veteran broadcaster related an incident early in his career when he was given faulty scuba-diving equipment.

Prince William and Sir David Attenborough explore the urgent peril of the world’s oceans, ahead of World Oceans Day and William’s speech at a global conservation summit