The National Theatre’s current Platform series on the century’s 100 best plays has so far turned up most of the usual suspects. But tonight it reaches one of the great forgotten dramas of the past 30 years: Heathcote Williams’ AC/DC. This anarchic piece - an award-winning success at the Royal Court’s Theatre Upstairs in 1970 - attacks the media’s influence with such extraordinary viciousness that it seems far more relevant now, in our multi-channelled, spin-doctored, news-obsessed world, than when it was first written.