On World Population Day, Helen Haran of St.Albans Population Matters explains why Sir David Attenborough thinks we need to act on our exploding population, and Malcolm Hull of Herts and Middlesex Butterfly Conservation wants us all to spend 15 lovely minutes looking at butterflies.

On World Population Day, Helen Haran of St.Albans Population Matters explains why Sir David Attenborough thinks we need to act on our exploding population, and Malcolm Hull of Herts and Middlesex Butterfly Conservation wants us all to spend 15 lovely minutes looking at butterflies.