I'm not up at 6 am. I start listening to the incoming news at 6 am. I'm not up until 7. By then I've heard the agricultural news, the news and financial news and listening to radio. Lying in bed relaxing. Quite busy after one has got up. There's quite a lot to put away from the night before, last night's papers to finish off, getting up and seeing what I have for the day. And just getting my thoughts in order for the day. I have very little breakfast. It tends to be a rather busy time because there's a rather lot going on.

Stay in your mental pyjamas all day. […] Work in the morning, a short break for lunch, work in the afternoon and then watch the six o’clock news and then go back to work until bed-time. Before bed, listen to Schubert, preferably some songs.

Generally, my hours are during the first part of the day; hardly ever in the evening. The hours nearer noon, the zenith of the day, are good for working.

You know, down the hall and up the stairs from this office is the part of the White House where the President and his family live. There are a few favorite windows I have up there that I like to stand and look out of early in the morning. The view is over the grounds here to the Washington Monument, and then the Mall and the Jefferson Memorial. But on mornings when the humidity is low, you can see past the Jefferson to the river, the Potomac, and the Virginia shore. Someone said that's the view Lincoln had when he saw the smoke rising from the Battle of Bull Run. I see more prosaic things: the grass on the banks, the morning traffic as people make their way to work, now and then a sailboat on the river.

The friends with whom I sat on graduation day have been my friends for life. They are my children’s godparents, the people to whom I’ve been able to turn in times of trouble, people who have been kind enough not to sue me when I took their names for Death Eaters.

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.

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 why do I talk about the benefits of failure? Simply because failure meant a stripping away of the inessential. I stopped pretending to myself that I was anything other than what I was, and began to direct all my energy into finishing the only work that mattered to me. Had I really succeeded at anything else, I might never have found the determination to succeed in the one arena I believed I truly belonged. I was set free, because my greatest fear had been realised, and I was still alive, and I still had a daughter whom I adored, and I had an old typewriter and a big idea. And so rock bottom became the solid foundation on which I rebuilt my life.

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

Even though I have a highly visual imagination, I’ve had to learn just how much can be said onscreen without a word, and David and Steve have taught me that.