When you go to see someone at Harmondsworth Detention Centre near Heathrow, you sit in a waiting room until your ticket is called and you are led into the large visiting room. After a while, the person you are there to visit enters through a door on the other side. The waiting room and visiting room are decorated with photographs printed onto canvas. The photos are the stock kind you might get on the desktop of a Windows PC: deserts, beaches, lush forests, drops of water, lands of mineral richness. They appeared after Mitie took over running the centre from GEO (both are private companies). Artwork by detainees used to decorate the walls, but now those pictures are stacked up in the corner.