Odd that you think of Jerusalem as an English Hymn, WAV, but otherwise it fits your mad schemes quite snugly. The opening lines refer to a legend of a young Jesus visiting (as an eco-tourist no doubt) England - specifically Glastonbury - with his uncle, Joseph of Arimathia, whilst the rest of it is couched in terms of a symbolic residence of a humanity freed of the inter-related chains of commerce, British imperialism, and war. Blake's mental fight is directed against these chains. In his Blake: Prophet Against Empire, David Erdman tells us that Blake's dark, Satanic Mills are the mills that produce dark metal, iron and steel, for diabolic purposes... London.. was a war arsenal and the hub of the machinery of war, and Blake uses the symbol in that sense.

Did Blake's visionary insanity extend so far as racism? Perhaps we shall never know, but it seems a shame that such a splendid piece of revolutionary polemic has been co-opted as not just a Hymn, which it never was, but our unofficial national(ist) anthem.