When the science fiction writer L. Ron Hubbard established the Church of Scientology back in the 1950s, he developed a system called the "Tone Scale". Designed as a way of classifying a subject according to how spiritually dead or alive they are, the Tone Scale ranges from 0.0 ("Body Death") to 40.0 ("Serenity of Beingness"). The average person, Hubbard wrote, is probably around a 2.8.
"Journalists," says Louis Theroux, "are a 1.1 on the Tone Scale. Which puts us on a par with sexual perverts ... I'm sorry to break it to you."
With this knowledge, it came as little surprise to Theroux when his requests to visit and film a documentary inside Scientology's towering Los Angeles headquarters were refused - "they sent me a long letter saying basically we have no intention of participating in your kind of journalism and want nothing to do with your approach."
In fact, in some ways it came as a relief. "I think I would have been worried [if they had said yes] because actually a little bit of access is sometimes worse than no access," he says. "I have a sort of freewheeling, free-flowing style, so I find it hard to work when there are conditions on what I can and can't say and do."
Instead, he went to Hollywood and started filming what would become My Scientology Movie. The documentary, which was released in cinemas last year, ostensibly chronicles Theroux's attempts to cast actors in order to recreate Scientology's internal practices and re-enact alleged incidents involving the church's controversial leader David Miscavige.
"At heart, what [Scientology] shares with all the stories I'm most interested in is that it's got some element of the extreme - allegations of misdeeds, rumours of it being abusive, of people acting against their most basic interests," he says.
He knew that by enlisting the help of former Scientologists to direct the re-enactments, the documentary would be likely to raise the ire of the church. "I have to be honest: I did hope that they would come out and wind us up," he admits. "It's a practice they call 'Confronting and Shattering Suppression'."
Sure enough, the film soon became as much about exposing the methods the church would employ to try and thwart the production LowdownLouis Theroux: My Scientology Movie
Tuesday, April 4, 7.30pm, simultaneously broadcast on BBC Knowledge and UKTV
I find it hard to work when there are conditions on what I can and can't say and do. Louis Theroux
Louis Theroux's Weird Christmas from his Weird Weekends series.
as it was about the re-enactments themselves. "We really document their attempts to harass and upset and intimidate us and our contributors," Theroux says. "To my mind, that is some of the most revealing material. There are very few groups or religions who are as aggressive or in-your-face when it comes to confronting their enemies."
Theroux's wide-eyed, bemused presence in the midst of these kinds of surreal and sometimes confrontational situations has been his trademark since his first BBC series Louis Theroux's Weird Weekends. Filmed in the late-90s, the popular TV documentaries followed his uneasy attempts to immerse himself in various "extreme" sub-cultures - UFO hunters one week, hardcore survivalists the next.
His idiosyncratic approach has earned Theroux a dedicated cult following, but on occasion has also rubbed a few people the wrong way. Unsurprisingly, given the subject matter, My Scientology Movie has drawn its share of criticism - most remarkably from one of its main subjects, Mark "Marty" Rathbun.
A senior and powerful member of the church before his departure in 2004, Rathbun's role in the documentary essentially is as Theroux's reluctant, sometimes prickly mentor on all things Scientology.
"As the film goes on, the gloves come off and he becomes more and more annoyed by our relationship," Theroux says. "I think you get this very enjoyable, almost buddy movie that emerges."
In a lot of ways Rathbun is the heart and soul of My Scientology Movie - an endlessly complex, conflicted character, he refuses to let things be simplified into black or white, good or evil. He defends the church as much as he condemns it. He is the kind of character Theroux has always gravitated to.
But shortly after the film's release last year, Rathbun launched a stunning attack on Theroux and the film's producers on his blog, writing in one post that he felt the documentary-makers had used him and other former Scientologists as bait to manufacture confrontation and provoke aggression from the church.
When asked about these claims, Theroux is quick to defend his methods, saying dealing with Scientology is "like being in a relationship with someone with a borderline personality disorder -- there's so much they don't like that you can start to become insane yourself if you attempt to tailor your behaviour to avoid annoying them. In a sense, you have to just play your natural game, and I think it's reasonable to go and film outside their base, I think it's reasonable to do re-enactments. All of those are valid techniques."
He describes his current relationship with Rathbun as "distant ... I still feel affection for Marty, but he didn't reply to my last email. "
There is a wider context to Rathbun's disavowal of the film, Theroux suggests, in that he appears to have become fed up with the whole world of Anti-Scientology -- describing it as being, in its own way, as cult-like as Scientology. "He's gone on to denounce a book that appeared about David Miscavige that was written by his father Ron (Ruthless: Scientology, My Son David Miscavige, and Me), and he's also turned his guns on one of the leading bloggers against Scientology, a guy called Tony Ortega.
"So there's something going on where he no longer feels comfortable being the go-to guy for anti-Scientology. And to some extent, I don't blame him, because he's been through so much crap and had so much thrown at him by the Scientologists with 'Squirrel Busters' [a harassment group who target ex-Scientologists] camping outside his house, with all the stuff that's written about him online."
Despite the fallout, Theroux is still glad to have been able to make My Scientology Movie with Rathbun. "Marty is unique among people who've left Scientology because he was so senior inside it," he says. "I felt when I was with him a lot of the time very much as though I was still with the Scientology Marty, you know? He has a quality of authority, of commanding people and not suffering fools gladly. Certainly I think Scientology has left its stamp on him, and he left his stamp on Scientology."