I am in a big warehouse painting skirting boards and door frames a gun metal grey. The hastily constructed stairs do not quite lead to the right places, so I can't reach everywhere I need to. A young artist asks me to work on her harebrained project, painting portraits of visitors on the walls engaged in intimate activities. I tell her I am not able to help so she will have to find someone else. "Don't mess up my paintwork," I tell her. "Oh we will have to..." she says casually.