Dennis Potter’s most controversial piece, Brimstone and Treacle, opens at the Arcola this week. Directed  by Amelia Sears and starring Rupert Friend, it is the first major London production of the work, which was originally banned before transmission by the BBC. Set against a backdrop of the Queen’s Silver Jubilee in the summer of 1977, this is a timely revival.

Dennis Potter is perhaps best known for his hit TV drama series The Singing Detective (1986), recently re-shown on BBC One, and as fans of the show will know, Potter’s work doesn’t date. It crackles on the borderline between fantasy and reality, and Brimstone and Treacle is as relevant now as it was in 1976. So why hasn’t it been put on sooner? “Because it’s really dark”, says Friend’s co-star Matti Houghton, who herself is no stranger to staring the darker side of human nature in the face – recent work includes the lead role in Antigone (Manchester Royal Exchange) and the incestuous Annabella in ‘Tis Pity She’s a Whore (Liverpool Everyman). A few days before first night, Houghton shared some of her thoughts on the play. For starters, Houghton can’t understand why it has taken so long for this superb piece of writing to be recognised. She plays Pattie, the daughter of Mr and Mrs Bates (Ian Redford and Tessa Peake-Jones), who two years ago was severely injured in a hit and run car accident and left incapacitated, confined to the living room of her parents’ suburban home. The middle-aged, lower middle-class couple struggle to come to terms with what has happened to their daughter, when a visit from an apparently respectable young man (Rupert Friend) changes their lives forever. As a twisted tale about fear and morality unravels, there are no easy answers to be found in Potter’s unsettling four-hander.

I asked Houghton what the atmosphere has been like in the rehearsal room: “It’s been brilliant. I’ve done a lot of really traumatic plays and actually weirdly those are the ones you have more fun on – because you sort of have to. I think when the subject matter is so dark you have to have a light rehearsal room otherwise it’s all too much, whereas with the comedies I’ve done it’s always been really miserable.” One thing that crops up again and again while talking to Houghton is the question of the past. While Brimstone and Treacle remains a controversial piece – especially in the close space of a studio theatre – it is also “quite a period piece”, she says, “and the language is quite period […] so it represents a very particular time in history. Class-wise it’s very interesting. They are a sort of lower-middle class family who are desperately trying – you know they have loose-leafed tea and they do their coffee properly, they don’t have instant coffee and there’s all these references to very sort of period things.”

But while a Jubilee backdrop and the heights of tea-time sophistication in 70s middle England might seem quaint at first glance, it’s worth remembering that next month England will be hurled once more into the world of flag-waving parades and commemoration mugs. Things haven’t changed completely and Houghton is quick to warn against the allure of nostalgia: “There are a lot of references in the play to how we want England to be how it used to be, this kind of nostalgic thing and I think that for me that’s what royalty sort of represents: a nostalgia for the past. That’s why people like kings and queens – because you like this idea ‘this is what England is meant to be like’, and in fact England is changing and thank God it did. But the play is right on the brink of big, big change and people are scared. You know, because of what was happening in suburbia and the industry changing and mass immigration happening, and there’s a lot of references to that in the play. And culturally, too, if you think about what’s happening for women – getting emancipated and sex changing and the pill being invented and all of that kind of revolution that happened between the 60s and 70s.”

I asked Houghton how Pattie fits into all this, crucially in the context of her disability. “The neurologist said that he thought it was a conversion disorder, which is this really extraordinary thing where it’s basically psychosomatic – so it’s completely real – whatever is happening to her is completely real but medically there is absolutely nothing wrong with her and it’s about the body’s way of dealing with stress […] i.e. you lose your speech completely, and if your parents think you’re brain-damaged and strap you to the bed, you would actually lose the use of your legs very quickly, because you just lose muscle tissue.”

And the treatment back then? “They wouldn’t have known what it was. They wouldn’t even have had CT scans or MRI scans so they would have taken one look at her and gone well she hasn’t got a fracture so she’s best out of here and we don’t really know what’s wrong with her […] The way they deal with conversion disorders now is through talking therapy. Instead, her dad is in complete denial that anything that’s happening to her that she can understand. So a lot of the first part of the play is her trying to communicate with them and them kind of ignoring her, so it’s pretty awful.” I asked her how she has managed to prepare for such a demanding part: “Well, our director is really fantastic and all the work we’ve done round the table has been very detailed. I’ve basically worked out my own language so that everything she’s saying I know what I’m saying or at least what I’m trying to say so that it’s very clear – so just like I’m talking now except that the words are coming out as sounds rather than as words.”

Houghton admits she thrives on difficult parts like these; they are why she is in actor: “Anything grim on the stage and basically I’m your girl. My first job out of drama school was this German play called Stallerhoff and I did that at the Southwark playhouse for £100 a week. I had to do everything that you never want to do on stage in that part, but it was an amazing play and it kind of pushed all the limits, you know, nudity, sex, everything. Personally I think life is dark and yeah you can go and see a play that is sort of escapist but you can also go and see plays that challenge you and make you think differently about things. That make you understand a family in a very, very difficult situation in a way that if you go and see something light-hearted you don’t get, and I think especially in studio theatres you are complicit and you are confronted with a lot of things that we don’t want to think about every day and, personally, that’s right up my street.”

Brimstone and Treacle opens at the Arcola Theatre Studio 2 on 2 May and runs until 2 June. After-show readings of other work by Dennis Potter are being held on Wednesdays. See the website for details.

Image credit: Rupert Friend as Martin Taylor by Faye Thomas