If we and the rest of the back-boned animals were to disappear overnight, the rest of the world would get on pretty well. But if the invertebrates were to disappear, the world's ecosystems would collapse

Steve Irwin did wonderful conservation work but I was uncomfortable about some of his stunts. Even if animals aren't aware that you are not treating them with respect, the viewers are.

I'm no longer sceptical. I no longer have any doubt at all. I think climate change is the major challenge facing the world.

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.

Climate change will affect the whole of humanity, while terrorist attacks will only affect a small section of humanity. Of course, you wouldn't say that if you were related to someone who had been beheaded or blown up or murdered.

Being in touch with the natural world is crucial.

Its about cherishing the woodland at the bottom of your garden or the stream that runs through it. It affects every aspect of life.