This year sees the 50th anniversary of Heathcote Williams’ The Local Stigmatic, which follows two sociopaths obsessed with celebrity culture. First performed in Edinburgh in 1966, the play was later made into a film starring Al Pacino. Michael Toumey’s new production remains faithful to the 1960s setting in which the play was written, and yet the story still feels chillingly relevant in our modern world of social media and reality TV.

Graham (Wilson James) and Ray (William Frazer) are two friends who spend their time gambling, getting thrown out of pubs and reading newspaper gossip columns. When they bump into David (Tom Sawyer), a slightly famous actor, the two befriend him – but their twisted game takes a sudden, shocking turn, revealing their deep resentment of the celebrities they follow so religiously, and the depths to which they’re willing to go to prove their own superiority.

Wilson James and William Frazer give two unforgettable performances as Graham and Ray, subtly highlighting the differences in their personalities. Graham is the undoubted leader; his wide-eyed, unblinking stare (which he occasionally fixes on terrified audience members) gives the impression of a man on the brink of madness, and yet we soon discover beneath it all he’s always in control, choosing and pronouncing his words carefully to manipulate those around him.

Ray, on the other hand, is arguably the scarier of the two – though physically much more relaxed, and even occasionally quite funny, he too carries a pent-up rage that occasionally explodes in violence, and his blank-faced subservience to Graham, particularly in the closing minutes of the play, is truly chilling. Tom Sawyer’s David never stands a chance against this pair as, clearly flattered by their attention, he’s led neatly into the trap.

The dialogue is fast-moving and laden with meaning; it’s the sort of script that needs to be heard more than once to catch all the references (it also helps, I think, if you have a little knowledge of dog racing). What is clear is the way phrases are repeated throughout but with shifting significance, as the piece builds towards its shocking conclusion. And it is truly shocking, though not in the way I expected. When you’re braced for blood and gore, the violence initially seems a bit tame… but its power lies in the ability to send our imaginations into overdrive to fill in the gaps.

A simple set allows the actors to move easily between home, where celebrity posters adorn the walls, and the outside world, whilst keeping the two distinct. Tom Kitney’s lighting helps create an increasingly tense atmosphere, and sound designer Neil McKeown uses 60s hits to great effect both between and during scenes, to ensure some of the most powerful moments are those where no words are spoken.

The Local Stigmatic is an extreme example, but we only have to look at the increasingly common occurrences of internet trolling, or read the comments on any article in the Daily Mail sidebar, to realise the resentment felt by Graham and Ray towards the rich and famous is still shared by many. And now that we live in a world where we don’t even need to be stalkers to know all about the lives of celebrities we follow – a word used with startling prescience in Williams’ script, written long before Facebook or Twitter had even been dreamed of – this 50-year-old play feels more relevant than ever.