Grey Smoke Yellow Sky depicts Portobello Power Station in Edinburgh, which was decommissioned in 1977. It was a subject which Peploe painted a number of times, attracted to the dirty, industrial light and abstract masses created by building and smoke. These coal-fired generators are long gone, part of a guilty fossil fuel era, and now carry a stigma, thought of as ugly scars on our suburban landscape. But to the artist they had a haunting beauty and, as the last vestiges of a Victorian fuel economy, a poignancy also.