Just released on digital, Fanny Lye Deliver'd is a real find. It's a retro delight that will have The Wicker Man worshippers, lovers of The Lighthouse and anyone whose formative experience of appointment-to-view involved the horror double bills on BBC Two raising a toast to writer-director Thomas Clay. His home brew is the strongest of stuff - "laced with shrooms", as one character helpfully explains.

Set in Shropshire in 1657, these desperate hours down on the farm throw fugitives Thomas and Rebecca (played by Freddie Fox and Tanya Reynolds) at the feet of Fanny (Maxine Peake), a woman who "has only known the land, the toil and the war"; her cruel Puritan husband John (Charles Dance) and their young son Arthur (Zak Adams). No sooner have the new arrivals been given some clothes and food than the power plays begin - and it's anyone's guess who'll be alive to see next Sunday.

Below, Freddie Fox talks about being part of a new cult classic.

Harry Guerin: Congratulations on a superb job. What was the one thing above all others when you read the script that made you say, 'I'm in'?
Freddie Fox: In all ways the script was terrific and unusual. 'A chamber piece hallucinogenic Western, set on a pig farm in the 17th Century' - who wouldn't want to be a part of that?! Added to which Thomas' (Clay, writer-director) characters were so well drawn. The dialogue and references had been meticulously researched to chime true to the speech of the period. And the tone, I think we can all agree now, had prescience that perhaps even Thomas couldn't have foreseen when he wrote it. Even though it was a period piece about a relatively undocumented, though hugely influential period of history, it read like a poetic thriller. To have seven-eight page scenes of dialogue in Olde English with Charles Dance and Maxine Peake, to be shot in one flowing, uninterrupted take on 35mm film… That's pretty much a once-in-a-career experience. I was determined to give it my best shot at the audition. 

Some people will see it as a Western, others will see it as a horror. Tell us more about your take on it.
Whilst most definitely a genre piece, I think part of the film's unique charisma is that it isn't immediately definable as one or the other. It depends on your disposition. Though I would say I always envisaged it as a Western of sorts, particularly when Thomas told me his cinematic influences before we started shooting. All the wide lens close-ups, and tracking shots and zooms feel very Western in style, which I loved. I guess, though, first and foremost it's a character piece, like a [Michael] Haneke movie in a way. It's rare as an actor to get such good material to explore on film. 

With director Thomas Clay on the set 

Did you see your character Thomas as a villain with a heart or a good man with some badness in him?
Probably the latter, I would say. Like most of us. I suppose you always look for a character's positive qualities first, then discover the trauma that creates the shadow side. So I guess I saw him first on a mission to secure his and Rebecca's safety, followed by a mission to sexually and spiritually emancipate Fanny. Undoubtedly he derives selfish pleasure from getting one over on John and the system he represents - at the unintended expense of Fanny, Rebecca and Arthur too. But that's somewhat explained, though not excused, by the traumatic hell he's experienced when fighting against the Irish. He's very fallible, often very selfish, but basically human. 

You roughed it in the back of beyond in Ireland for Black '47. Was it a tougher shoot physically than Fanny Lye Deliver'd or were they both as bad as each other?
Black '47 wasn't a patch on Fanny Lye. Fanny Lye was a unique experience in many ways, most of them very good, though the confines and demands of the shoot were singular in their 'toughness'. I mean, it wasn't the jungle with Werner Herzog, but it was maybe a close runner-up. I think, however, that's what created such a strong bond between the cast and crew, many of whom will be friends for life. So in a way I'm grateful for it. I will never forget it, that's for sure.  

"A once-in-a-career experience"

Fanny Lye Deliver'd is very much a celebration of 70s cinema in terms of style and technique. Did that pose any challenges in terms of performance?
Some, mainly in regard to the exactness of the camera movement, the light, and the frame, and how performance was sometimes a secondary thought to those concerns. Though again, I would say in the end the challenges were worth it for the end result. Thomas's vision was totally singular, and in the end we all wanted to make a singular film, so the precision was necessary.  

Were there any touchstone films you watched in preparation?  
Not really. I didn't have time, to be honest, as they'd already started shooting by the time I was cast. I watched some John Ford documentaries about shell-shocked soldiers coming back from Vietnam - or possibly WWII, I can't remember now - that were very interesting about the lingering trauma of war and how that effects its survivors. However, mainly I just dived in and hoped I'd swim. 

With co-star Tanya Reynolds

What does the film say to you about human nature? 
I think one of the lingering messages of the film is that repressing the female person or spirit is a terrible crime, that it's been happening for centuries, and in Thomas Clay's world it's punished with an iron fist. However, I think it's also an interesting study of dependence vs independence, and how fallible we all are, especially when in a position of power. At the end of the day, though, it's called Fanny Lye Deliver'd. It's her story, so it's first and foremost a film about historical female suppression and her burgeoning desire to be free and treated as an equal.

You've worked with your co-star Charles Dance a number of times, including on the short film you directed, Hero. Did Hero happen before or after Fanny Lye Deliver'd?
Charlie's been a friend and mentor to me since I was a boy, really. I'm so lucky to have worked with him as many times as I have, both as an actor and director, and for everything he's taught me and is still teaching me about both disciplines. Hero was a direct result of working on Fanny Lye Deliver'd. It was shot the following summer and many of the crew we worked with, like Leo Arvanitis, my amazing Director of Photography on Hero, I met on Fanny Lye - another of the film's lasting positive legacies. When we were shooting Fanny Lye, Charlie and I lived together in a cottage not far from the set, so we ended up forming a strange Odd Couple bond!

Maxine Peake as Fanny and Charles Dance as John

You're on a great run with Watership Down, White House Farm, Year of the Rabbit and now Fanny Lye Deliver'd - and The Crown yet to come. What have you learned about yourself along the way and about success?
I think mainly that I'm very lucky to have worked. So many of my friends haven't been so lucky though are undoubtedly as talented, if not more so, than me. So the end goal for me is just to work, and hopefully on interesting characters with people who like to laugh. And who knows? Maybe direct a few more pieces along the way with any luck. That's certainly one of my main ambitions going forward. 

Fanny Lye Deliver'd is out now on digital.