Grade: A-

One of the best one-liners attributed to Sir Thomas Beecham refers to the stridently avant-garde Karlheinz Stockhausen: ‘I’ve never conducted his music, but I once trod in some.’ It’s almost certainly apocryphal, but the implied verdict is widely shared. Stockhausen played up to the caricature of the self-obsessed ‘squeaky gate’ composer, though his capacity to create painful noises went way beyond squeaks: only he could have written a string quartet in which each player is recorded in a separate helicopter.