There are horrors in the world so vile that few of us want to think about them. None more so than such cases as Josef Fritzl - or Jaycee Lee Dugard, or Arcedio Alvarez, or Raymond Gouardo, or Wolfgang Priklopil, or Marc Dutroux... but you get the picture. Cases where men abduct girls and turn them into sex slaves and father multiple children by them, often incestuously, hiding them in garages, basements, behind walls, sometimes for decades undiscovered, sometimes murdering them. Mostly you read that it happened, you shudder, and try not to think more about it.

Critics did not cover themselves with glory after the premiere of The Sleeping Beauty in St Petersburg on a snowy January night in 1890: “We cannot help regretting the means chosen by the theatre directorate in lowering the standard of artistry of our ballet,” wrote one. Another: “Such spectacles attract neither a constant public nor a circle of educated adherents.”