I’m jolly surprised to make it to 80, because I was a very sickly child – I had chronic asthma. I take an inhaler daily to keep it at bay, but it’s always there. I’m doing less and less exercise because of a back injury, too, but our house has about 80 steps and I walk up and down to my studio at the top quite a lot. I’ve noticed non-asthmatics huffing and puffing when I’m not.

I stand at my desk, which is healthier. Unlike most artists who work from the wrist, I work from the shoulder – I swing at the paper.

I try not to do something in a routine way. There’s a danger of falling back on doing what you know you can do. I’ve always tried to push my drawings and make them more extreme. I often look back to the 18th century – to Gillray and Hogarth – for inspiration.

I’ve got a model of the pterosaur that was found on the Jurassic Coast and was named after me, Cuspicephalus scarfi, because it reminded them of my drawings of Mrs Thatcher – it’s got a very beaky nose and it’s rather aggressive. It’s nice to have made it to a really old codger!

I can’t imagine retiring. I get a kick out of wondering what’s going to come out on the paper, and the great thing about a deadline is that it squeezes that last piece of toothpaste out of the tube.

I can get very angry with myself, not having achieved what I think I should have achieved. That goes way back to my childhood. My parents thought I’d never make a living or do anything – I was uneducated really, because of so much absence from school.

I am a worrier, but I try not to be. I’ve had a rather anxious passage through life, but I’ve also been incredibly bloody lucky. I’ve done so many things I never thought I’d do.

The new menu at Scarfes Bar, Rosewood London, features cocktails inspired by Gerald’s work (scarfesbar.com)