Robert Winston

I don't believe in regretting - one should try to move on. My mum was good at that. She was deeply in love with my father, and he died when I was nine. She remarried, and her second husband died, too. I saw the grieving process she went through. My mother had this way of moving on. It was a fine trait.

Childhood is not dead. Children were worse off when we were hunter-gatherers; they were threatened in medieval times and exploited during the Industrial Revolution. Was it any better in the time of Charles Kingsley or Charles Dickens?

I've never had much interest in spinoffery - the idea of writing in someone else's universe generally leaves me cold - but 'Doctor Who' is different. I've grown up with it. It's been part of my life since I was tiny, watching Jon Pertwee on a grainy black and white television in Cornwall and being terrified out of my mind.

Though builders may build, in the main they follow the plans of architects. Teachers teach, but they must have a text. Politicians govern, but only upon the flow of commentary that raises them up or casts them down.

When we human beings hypothesize that a law of nature holds - even temporarily or situationally - we are creating an idea, but we are also making a hypothesis about how nature behaves, whose truth or usefulness has nothing to do with what we know or believe.