As stated earlier, I think it's very important to remember the general griminess of the buildings in wartime Britain, London especially. There were fourteen mainline terminus stations - Blackfriars, Cannon Street, Charing Cross, Euston, Fenchurch Street, King's Cross, Liverpool Street, London Bridge, Moorgate, Marylebone, Paddington, St. Pancras, Victoria and Waterloo. All of them were served by coal-burning steam locomotives hauling trainloads of produce into the capital city, every hour of every day! In addition to the passenger stations mentioned above there were also freight termini like Somers Town, situated adjacent to Kings Cross, where all the potato traffic of the country arrived. London was the major distribution node for the South of England for farm produce and much else besides.
I'm sorry to be getting off the point here
What I'm trying to stress is that London ran on coal. It burned in every domestic fireplace, fired all the power stations, ran the railways and shipping fleet and was turned into gas at the coking plants. It was everywhere - and its effluent stained every building in the whole city! It was not until the mid-sixties when steam power was phased out, and the Clean Air Act was made law, that work started on cleaning the civic buildings of London. This overall griminess is essential to show the true condition of 30's London.
brando