For me, this was a thrilling evening at the Theatre Royal Windsor. Pretty much all the stops were pulled out to build a sense of unease and brooding malevolence. As we took our seats the auditorium was rumbling, a bell tolled in the distance, and I swear I saw someone or something from the corner of my eye…

The 1973 film of The Exorcist was a landmark in horror, but this play is John Pielmeier’s 2012 adaptation of the original novel, and is somewhat different from the famous film. Instead of the rather slower burning build-up of the movie, we are immediately within Chris McNeil’s sinister rental home and her dysfunctional circle. The film director, Burke, fairly minor in the movie, is here a much more significant player, with perhaps the most intriguing part, played with relish by Tristram Wymark. With pathos and humour, he confesses guilt for making movies that he didn’t care about so long as people bought tickets, and regrets the hubris with which he has lived his life. This theme of guilt is everywhere. The end of her marriage and the dislocation of Regan’s life are just the more obvious aspects of Chris’s feelings of regret. Father Damien Karras’s priesthood constrains and frustrates him, and he is tortured by regret over the end of his mother’s life, contrasting the beauty of her motherhood with the inevitable cruelties of old age. These are familiar human feelings that many if not all of us can empathise with, but are the raw materials that Regan will throw back at them in the cruellest ways imaginable.

As with the “real life events” and the William Peter Blatty source material, it is unclear if Regan is demonically possessed by supernatural evil, or psychologically disturbed by what others have done. The girl’s vulnerable age, at the blurred transition from the neediness and innocence of the child to the dawning of teenage independence and sexuality, is calibrated for maximum discomfort, and Susannah Edgeley very successfully portrays Regan as a girl much younger than herself. The “demon” tempts her by playing on the feeling that no-one loves her, but he does. The play taps into other very contemporary themes; how suffering begets suffering, how circumstance and unintended consequences can result in misfortunes leading to lifelong misery. Damian argues that as we have evolved, we have weakened the devil, yet it has made him more dangerous; the point perhaps being that as our lives become more comfortable and secure, existential risks may become greater. When Father Merrin advises Damian that the devil will mix lies with truth to confuse him, he could be warning against that most modern phenomenon of fake news on social media.

This is an impressive staging with a clever split level set, and very high quality sound and lighting effects, the whole production being designed to maximise the feeling of horror. The performances were admirable all round, although I wonder if some English actors seem distracted by using American accents, and I’m not convinced that it was really necessary in this case. No doubt as they take this production on tour everything will become slicker, though Tristram Wymark, having played this part previously, already seemed fully at home in his role as the English film director, and Susannah Edgeley has already nailed it as Regan.

I found the play to be gripping throughout, the pacing and tension of the first act being especially effective, with perhaps the opening minutes of the second act slackening things off slightly as it becomes a little talky – albeit some of that talk is with the devil. The tension certainly builds again, with the arrival of Paul Nicholas as Father Merrin, cranking up the gravelly voice, and Susannah Edgely particularly impressive as the fully demonic Regan, lip synching to Sir Ian McKellen’s masterful recorded performance as the devil. Between them they propel the performance kicking and screaming to a resounding climax, during which I found myself sitting bolt upright with my mouth open. Not just an exciting horror story then, but clever and thought provoking, and superbly staged.

This Bill Kenwright production of The Exorcist continues at the Theatre Royal Windsor until 14th September, following which it will tour the UK and Ireland.