The box office was mobbed and the overflow audience watched the action on a TV screen outside the auditorium. Leigh knew the play was popular - it was a sell-out for two runs at Hampstead, received well as a BBC Play for Today in the same year and, when repeated for a second time in August 1979, around 16 million people watched - but nothing could have prepared him for that night on the South Bank. Perhaps he shouldn’t have been so surprised.

In the 30 years since Abigail’s Party was first shown on television, the drama has taken on a life of its own. It is a simple story brilliantly done: Beverly and her husband Laurence host a drinks party for a few neighbours in their suburban house. The guests - Angela, her husband Tony, and Sue, a divorcee whose daughter Abigail is having a rowdy party nearby - are subjected to Beverly’s desire to be an exemplary hostess.

Swishing around in her voluminous dress, she plies them with alcohol and nibbles. After a series of awkward silences and arguments about music and art, Laurence, tense from the outset, dies of a heart attack.

Beverly, the personification of the gauche, aspirational hostess, has become a gay icon and a drag-queen favourite; there are Abigail’s Party parties where fans recite lines to one another (Beverly: ‘Tone? A little cheesy-pineapple one?’) People are endlessly drawn, it seems, to finding inappropriate moments funny: it’s even hard to stifle a horrified laugh when Beverly flicks ash over Laurence as he lays dying.