Natural history is not about producing fables.

The truth is: the natural world is changing. And we are totally dependent on that world. It provides our food, water and air. It is the most precious thing we have and we need to defend it.

We really need to kick the carbon habit and stop making our energy from burning things. Climate change is also really important. You can wreck one rainforest then move, drain one area of resources and move onto another, but climate change is global.

The more you go on, the less you need people standing between you and the animal and the camera waving their arms about.

The fact is that no species has ever had such wholesale control over everything on earth, living or dead, as we now have. That lays upon us, whether we like it or not, an awesome responsibility. In our hands now lies not only our own future, but that of all other living creatures with whom we share the earth.

In the old days... it was a basic, cardinal fact that producers didn't have opinions. When I was producing natural history programmes, I didn't use them as vehicles for my own opinion. They were factual programmes.

Opponents say natural selection is not a theory supported by observation or experiment; that it is not based on fact; and that it cannot be proved. Well, no, you cannot prove the theory to people who won't believe in it any more than you can prove that the Battle of Hastings took place in 1066. However, we know the battle happened then, just as we know the course of evolution on earth unambiguously shows that Darwin was right.