One day, out of irritation, I said, you know all of those years with the Royal Shakespeare Company, all those years of playing kings and princes and speaking black verse, and bestriding the landscape of England was nothing but a preparation for sitting in the captain's chair of the Enterprise.

What identifies an individual as a king is how other people behave towards him. All authority is assumed, and if other people don't accept your authority then you don't have it. Perhaps the critical thing to being a convincing figure of authority is actually not to try too hard.

I was brought up in a very poor and very violent household. I spent much of my childhood being afraid.

Laurence Olivier said if you have ambition to be a serious classical actor, you must be as fit as an athlete. For me, the breakthrough was going to live in California. I exercised. I drank less. It was one of the things about California that had a positive impact on me.

I know it feels like two steps forward and one step back, but we are making progress. In my lifetime, I have lived through one World War, I have lived through the end of Apartheid in South Africa, the pulling down of the Berlin Wall. I have experienced what I never thought I would have experienced, which is a pretty workable peace in Northern Ireland, and I experienced a unified Europe - until the Conservative government got its hands on the idea that in order to appease a few back-benchers they would hold a referendum, what a disastrous idea.

As a child, I heard in my home doctors and ambulance men say, 'Mrs. Stewart, you must've done something to provoke him.' 'Mrs. Stewart, it takes two to make an argument.' Wrong. Wrong! My mother did nothing to provoke that - and even if she had, violence is never ever a choice that a man should make. Ever.

Having played many roles of scientific intellect I do have an empathy for that world. It's been hard on me because flying the Enterprise for seven years in Star Trek and sitting in Cerebro in X-men has led people to believe that I know what I'm talking about. But I'm still trying to work out how to operate the air conditioning unit on my car.