‎Using his burgeoning intelligence, this most successful of all mammals has exploited the environment to produce food for an ever increasing population. Instead of controlling the environment for the benefit of the population, perhaps it's time we controlled the population to allow the survival of the environment.

There are perfectly good independent small nations.

We keep putting on programmes about famine in Ethiopia; that’s what’s happening. Too many people there. They can’t support themselves — and it’s not an inhuman thing to say. It’s the case. Until humanity manages to sort itself out and get a coordinated view about the planet it’s going to get worse and worse.

If I can make programmes when I'm 95, that would be fine. But I would think I'll have had enough by then.

You have to steer a course between not appalling people, but at the same time not misleading them.

I just wish the world was twice as big and half of it was still unexplored.

How could I look my grandchildren in the eye and say I knew what was happening to the world and did nothing.