Stirton's work, he says, is now all about investigation. 'You literally are trying to find out what's happening and, finally, manoeuvre yourself to the point where you can take a picture, and then you're presented with a 20-minute window where it's: Okay, now get your picture!' His voice is charged with emotion. 'Fucking angst and worry and, you know, FEAR of failure – every aspect of that comes into those 20 minutes, so it's a very intense experience. So when I make those pictures, I'm worried; I’m nervous.