Troublemakers was my first book. Like most of my books, it took a long time to write – more than two years from start to finish. That’s partly because I started off writing about a girl and then I had to change her into a boy!

The idea for the story came from a girl at the school where I was teaching. Some people came and did a beep test (if you know what that is) with all of the year 4 children, and this girl – let’s call her Sue – turned out to be the fittest child in the school. She was also dead keen on football, so I thought: what if someone like Sue turned out to be so good at football that a Premiership club wanted to sign her? They’d have to change all the rules. And she’d have to put up with lots of people thinking she’d never make it. Maybe even her own family.

A little later I had the idea of Sue meeting Chester Smith, a black footballer who was having a hard time because of racist taunts from the crowd, and then I really got stuck in to the writing.

You probably wonder why I changed Sue into a boy – Robbie in the story. Well, the publishers persuaded me that I’d sell more books that way, and I was desperate to get my book published so I made the change. Actually, I made lots of changes, and the book was published, so it was probably worth it. But I do still have a sneaking regret about Sue.