I think about bringing up our children all the time, and the thought is: we can’t mess it up, we have to do everything perfectly, otherwise they’re going to hate us for the rest of our lives. Safeguarding the anarchy and innocence of childhood is so hard to do now.

Looking back on my own childhood, it felt limitless. Summer holidays away from school felt like they went on forever. Anything before the smartphone was a utopia because we weren’t recording every minute of our experiences.

They gave out these leaflets at junior school for a dance, drama and singing group on a Saturday morning. My friend and I begged our parents to take us. Later my father worked as a TV producer at Central Television, and they funded a drama group. We had this fantastic teacher called Colin Edwards who treated us like we were at Rada. If it wasn’t for him, I wouldn’t be doing what I’m doing now.

I started in The Archers when I was 12. I remember sitting in the green room surrounded by people of all different generations and different walks of life. I learned a lot about being an adult in that room.

I don’t like seeing anything of myself in my performances. When I see a blink or a laugh I recognise as my own, I think: “You failed.”

Partly because you get so bored of yourself as you get older, you deliberately turn to roles with more complication and texture, stories you hope will affect some kind of influence in the world.

People often say Eddie Redmayne and I look so alike we could be twins. If you can’t laugh about that sort of thing, you’re going to cry. I’m an actor. I have to be prepared to put myself out there.

I wish I could get away with not having a smartphone. But then I couldn’t pay for parking. So I’m stuck with it. I always liked Bill Murray’s decision to have neither an agent nor a mobile – only a landline. Do you think that’s still the case? I wonder if he’s ever thought, “The work’s dried up a bit, I better get a mobile phone.”

I can juggle for about 12 seconds before I give up and have to start again. But apparently juggling is very good for dementia – so I should get back on with it.

I can’t get on a plane without sobbing. I get impassioned on a flight: you feel like you’ve solved the world’s ills, you’ve come to an understanding of who you are and why you exist, and you have a good cry. But once I’ve landed, all those epiphanies don’t seem quite as easy to enact.

I try not to look in the mirror too much. Madness lies that way – looking in the mirror is not where the truth is. The beauty of wearing contact lenses is that I can take them out at the end of the day and the world becomes beautifully blurred. It makes more sense like that than it does in sharp vision.

The Brutalist is in cinemas now