From the November 23, 2009 Financial Times: "Paul 'Moose' Curtis [above] founded Symbollix in 2003, after his particular brand of 'grime writing' — creating pictures and slogans by selectively cleaning the dirt off walls and pavements — caught the attention of corporate marketing departments."

I came up the idea of grime writing or reverse graffiti 10 years ago, while trying to promote a record that my record label was about to release. There was no marketing money, so I went to a tunnel in Leeds with a friend who was a great graffiti artist, and in seconds made a huge piece – just using an old rag and his fingers to write in the dirt. We had created legal graffiti. No one had ever invested any time in these tunnels and our work shone like chrome.

After that revelation, I carried on writing on walls as a means of self-expression. It was unique at the time. And it began to dawn on me that I could make money out of it. I had worked as a technician on events for the launch of the Xbox and showed it to the people I worked for – they programmed it into the launch a few months later. That’s when my hobby turned into a business. But I don’t refer to my work as reverse graffiti any more because of the negative connotations attached to graffiti.