Losing one of my children, as there is no greater loss.

Being homeless.

Pigeons. One got stuck in my flat once for quite a long time and it really changed how I feel about them.

Dying with a feeling of incompleteness.

I cannot possibly reveal the full horror of my most embarrassing moment, but it took place in a pub in Exeter (which is a town in the south coast of England, where I went to university) in 1984 and involved a joke made by me that backfired spectacularly. The whole debacle was witnessed by my friend Pauline, who is mentioned elsewhere on this fansite (I have to keep her happy in case she TELLS).

In my early twenties I wrote quite a lot of a very bad novel called The Private Joke. I regularly abandoned it for months at a time to write other things, then picked it up again. Part of the manuscript was sitting up in the luggage rack when, aged 25, I was travelling by train from Manchester to London, and the idea for a very different kind of book hit me: that of a boy who didn’t realise he was a wizard, and was taken off to magic school.

Moments of pure inspiration are glorious, but most of a writer’s life is, to adapt the old cliché, about perspiration rather than inspiration. Sometimes you have to write even when the muse isn’t cooperating.

So given a Time Turner, I would tell my 21-year-old self that personal happiness lies in knowing that life is not a check-list of acquisition or achievement. Your qualifications, your CV, are not your life, though you will meet many people of my age and older who confuse the two. Life is difficult, and complicated, and beyond anyone’s total control, and the humility to know that will enable you to survive its vicissitudes.

I couldn’t have asked for better collaborators on the stage play than John Tiffany (director) and Jack Thorne (writer).

I try to start work before 9am. My writing room is probably my favourite place in the world. It’s in the garden, about a minute’s walk from the house.