In the film, the shady director Santini didn't want his work The Equestrian Vortex classified as a horror movie, which leads to the inevitable question - how would you want Berberian Sound Studio to be classified?
"I see it as a work drama. For me, it's got a lot in common with The Office - that Ricky Gervais character is from Reading as well. It's about work, it's about hierarchy and all the problems with work - some very ancient problems to do with nepotism, corruption, bullying and sexism and so on.
"But if someone called it horror I'd be more than happy. The only reason I wouldn't call it horror myself is because we had a couple of screenings where horror fans came along and they were really, really pissed off, so I'm just very weary."
You mentioned The Office - could you see a parallel with the work-induced frenzy of David Brent doing his famous dance and Toby Jones in Berberian Sound Studio stabbing cabbages in front of workers?
"Haha, it didn't occur to me but maybe subconsciously it might have been there!"
As for addressing the needs of disgruntled horror movie fans, were you ever tempted to shoot any scenes for the film-within-a-film The Equestrian Vortex?
"No, it was always clear from the start that it had to be that way. I think in the last few years horror has become so extreme and you do feel that people try to outdo each other and you don't want to get into that. It's something other than filmmaking... a bit like who can drive the fastest.
"I thought, 'Why not do the complete opposite and not show anything whatsoever?' but still follow the same dynamics as a horror film. When you don't see blood and so on it's not going to be scary to everyone... but the main thing to achieve was to have the intensity that horror films have. I think the human brain is a lot more powerful than what we can put on the screen and the audience can readily compensate for what they don't see. Sometimes it's a lot more disturbing for that. People are a lot more actively involved in the film when you give them less."
Where did the original idea for Berberian Sound Studio - or the short film it was based on - come from?
"The short film came as a bit of a joke... but what came out of that film was this idea of two extremes - having a highly unpleasant violence on the screen but on the other side having this kind of pantomime element. How do you position yourself between those two extremes? It's very interesting to see with an audience.
"It's also about the nature of sound - and how context and association can change it. You have the very innocent sound of someone stabbing a cabbage, what you have when you cook a meal in the evening. But what if you give it a different context? It can be completely weird."
The jarring and unsettling nature of the sound led me to wonder whether David Lynch's Eraserhead was a direct influence...
"Not really. Eraserhead was a huge influence on me when I was younger. That was one of the first films I really, really got into. Maybe subconsciously, films that are really formative to you get under your skin. The 'Silencio' sign - that actually came from the word 'silencio' being used in a lot of [Ennio] Morricone soundtracks, but with a 'z' not a 'c'.
"Film-wise, I think the biggest influence was a film called The Cremator by a Slovak called Juraj Herz. The way he edited the film, his complete sense of geography blending into one by the way he cut between physical locations - we did this in Berberian by the way we moved between the studio and Gilderoy's apartment. That was quite an explicit nod."
Going back to the cabbage stabbing, I have to ask - how much was the cabbage budget for the film? A lot of them were used!
"Haha, I didn't know anything about the money - I still don't. I'd get raised voices if I was heading over budget. We had problems getting it to rot. We couldn't artificially make it look rotten so we had to do it for real. We had two troughs and left stacks of vegetables in there. It took a week to ten days and each day the smell in there was getting heavier and heavier. It reeked by the end but I really enjoyed shooting the vegetables."
The close-ups of the rotten cabbages had an extremely sinister quality. It felt as if my mind was trying to imprint meaning onto this imagery, even seeing a tortured, contorted face in the cabbage on one occasion...
"Well, we used them as substitute gore shots. We tried to follow those horror keynotes but obviously substitute them. For me, that first [rotten cabbage close-up] where we pull the focus reminds me of this strange planet in a Solaris-type world. There's a strange beauty to them. But there was always meant to be that sinister element.
"On one level they were comical with people chucking watermelons on the floor, but the more it builds up, the more it gets under your skin... it disturbs you. We had the same as filmmakers. Hearing stuff again and again and again, it really freaks you out sometimes. I had hours of screams, quite heavily manipulated. They do your head in at night sometimes. I can see why Gilderoy lost it."
Toby Jones is brilliant as Gilderoy and is one of the most underrated actors around. How did his casting come about?
"Shaheen Baig, who cast the film, suggested him. When we met, it did help that he liked the script as he knew the money was s**t. He was doing it for the right reasons, not the pay-cheque. Physically, I found him quite interesting."
Did Gilderoy simply just go crazy like Jack Torrance in The Shining or did the film 'possess' him in the end?
"It's a good question. I just did a commentary for the DVD and that was a tough one for me in terms of how much to explain and how much not to explain. I had a big dilemma - if I don't explain it's good on the one hand because it keeps the interpretations going, but on the other hand it could be a cop-out.
"It could be that he's gone mad, yeah. But it could be other things, like he's a conceptual construct and more of a cipher coming through the sound world. The nature of doing a repetitious work of any kind, whether it's sound or data entry in an office, it does get to you eventually. Structurally, the film is constructed like a loop. That's how people made sound with analogue - using a tape loop. The best example is Joe Meek, who completely lost it and turned to the occult, shot his landlady, shot himself."
The movie has an almost a fetishistic love for old-school movie making and the analogue process - so what are your thoughts on digital?
"I'm not anti-digital, I just don't like it when it's forced upon everyone. That's what's happening and I think everyone should have a choice. I would concede that analogue has its drawbacks especially in terms of the environment when you physically process film. If you've been to a lab and see the amount of chemical waste that goes on it's shocking. There's pretty nasty carcinogenic stuff in there as well.
"But I think film has this great beauty that digital can't match. We shot Berberian on digital by the way... but we still shot some sequences on 16mm, like the Box Hill sequence and the bit where the film breaks up. There are pros and cons to both. The sad thing is there is no choice. For my next film we're trying to shoot it on 16mm because we're painfully aware it's going to be outmoded within a couple of years. One last hurrah for film."
What can you tell us about your next film?
"I don't want to say too much because it's still in the writing phase. I'm doing it with Andy Starke and Pete Tombs, two guys I like a lot. They do Ben Wheatley's films but also they're involved in the Mondo Macabro DVD label. We've got so much to get through before we can start, but hopefully we need to get something together. I just need some quiet time to crack on with the script really and see if anyone wants to help Andy and Pete put it together. It's such a weird old industry - so up and down. You just never know."
Berberian Sound Studio is out now to buy on DVD and Blu-ray.