This is Coal Face, a GPO Film Unit documentary directed by Alberto Cavalcanti in 1935, overseen by John Grierson (the following year the team produced the more famous Night Mail). It was one of the most interesting things I saw at Manifesta, held this year in an abandoned coal mine. Cuauhtémoc Medina, Manifesta’s Mexican curator, calls this rather unusual collision of avant garde music, statistics, history, Marxism and poetry “docu-Modernism”. The music — by Benjamin Britten — is wonderfully estranging; it’s as if real miners are being turned into dancers in an esoteric revolutionary opera. Modernism, Marxism and mining were all systematically abandoned in Britain during the same decade, the Thatcherite 1980s. Thatcher wasn’t too keen on homosexuality either (both Cavalcanti and Britten were gay).