I feel a little like I had writers block for the first 32 years of my life and then suddenly, in the course of one weekend, it was gone. I had no intention of writing a book when I sat down and indeed, hadn’t even thought about doing so for some time. My 20s had been filled with poetry but nothing approaching a story or barely even prose.

However, one weekend in 2010 my wife and I headed to the Cotswolds, her to run a retreat and me to wash up for the weekend. We’d hired a cook to make sure that things ran smoothly. Fortunately she turned out to be more than a little efficient and I soon found myself relieved of all but table laying and ensuring that the urn was kept topped up. I sat down with my laptop, still with no real intention and opened a new word document.

Gazing down at the plain white screen I experienced the excitement that I always get when faced with a page of possibilities. In the past I would generally type, delete, type, delete, think a bit, type some more and then close without saving. This time however, the words seemed to fit together. Without knowing where I was going, some guy called Mars was throwing himself out of a helicopter and embarking on a mission across London. By the end of the day, I knew exactly where I, and he, was going and more importantly, why?