Kelly Marcel, the screenwriter behind Fifty Shades of Grey, has revealed she has felt unable to watch the salacious blockbuster because the final cut was so different to her “crazy and artistic” original vision.

Production of Sam Taylor-Johnson’s film was plagued by reports that author EL James clashed heavily with the British director on set, with the novelist keen to ensure a more literal take on her bestselling book. Now Marcel has revealed she was left so disheartened by the experience of working on Fifty Shades of Grey that she has not been able to bring herself to see it.

“My heart really was broken by that process, I really mean it,” she told Bret Easton Ellis’s podcast. “I don’t say it out of any kind of bitterness or anger or anything like that. I just don’t feel like I can watch it without feeling some pain about how different it is to what I initially wrote.”

Marcel said her plans for a non-linear reading of James’ novel were initially received with enthusiasm by studio Universal. But she eventually came to realise that the British writer would only sanction a final cut that cleaved tightly to her own famously clunky dialogue.

“I didn’t want the story to be linear; I wanted it to begin at the end of the film, and for us to meet in the middle,” said Marcel. “So you start with the spanking, and you have these sort of flashes that go throughout the film … I wanted to take the inner goddess out, and all of Ana’s inner monologue … I wanted to remove a lot of the dialogue. I felt it could be a really sexy film if there wasn’t so much talking in it.

“When I delivered that script was when I realised that all of them saying, ‘Yeah, absolutely this is what we want!’, and, ‘You can write anything you like and get crazy and artistic with it’ – that was utter, utter bullshit. Rightly so. Erika was like, ‘This isn’t what I want it to be, and I don’t think this is the film the fans are looking for …’ Ultimately, Erika did have all of the control.”

Reports prior to Fifty Shades of Grey’s February release alleged that James threatened to withdraw her support for the film unless her original dialogue was retained. Studio Universal hired the award-winning playwright of Closer and Dealer’s Choice, Patrick Marber, to hone Marcel’s James-sanctioned screenplay. But the novelist reportedly went through the final script and removed all Marber’s tinkerings, threatening to alert her fans on social media if she were challenged.

The author also reportedly refused to allow a subtle change to the film’s denouement in which Dakota Johnson’s Anastasia Steele was due to mutter the safe word “red” to Jamie Dornan’s kinky billionaire Christian Grey. In the final version, Taylor-Johnson and fellow film-makers were overruled, and Steele speaks the word used in the novel: “Stop.”

Taylor-Johnson admitted to fighting with James over the movie earlier this year, telling Porter magazine: “It was difficult, I’m not going to lie.” She has not signed on to direct follow-up Fifty Shades Darker.

Said Marcel: “There was a moment where we were weeks away from shooting … and it was clear that that was gonna be a struggle. It’s very difficult to come on as a director and to be handcuffed that way and not be able to fulfil your creative vision because there are certain restrictions on you. But at the same time, I would argue that it was very clear that that was the way it was going to be.”

James is to take even tighter control over Fifty Shades Darker, which is expected to hit cinemas in 2017. The novelist has hired her husband Niall Leonard, who has previously written for TV shows including Ballykissangel, Wire in the Blood and Monarch of the Glen, to oversee the new screenplay.

Universal can reasonably argue that its approach has proven a highly profitable one. Despite scathing reviews, Fifty Shades of Grey scored $569.6m at the global box office and is likely to be one of the top 10 movies of 2015.