Fifty years ago, when the WWF was founded there were about three billion people on earth. Now there are almost seven billion. Over twice as many - and every one of them needing space. Space for their homes, space to grow their food (or to get others to grow it for them), space to build schools and roads and airfields. A little of that space might be taken from land occupied by other people but most of it could only come from the land which, for millions of years, animals and plants have to themselves.

Presidential Lecture by Sir David Attenborough to the RSA on 10 March 2011