"The thing about 9/11 is that it’s basically an artwork in its own right,” he told the BBC. “It was wicked, but it was devised in this way for this kind of impact. It was devised visually. I think our visual language has been changed by what happened on September 11. An aeroplane becomes a weapon – and if they fly close to buildings, people start panicking. Our visual language is constantly changing in this way, and I think as an artist you’re constantly on the lookout for things like that."