Had a Hollywood screenwriter and a sci-fi nut got together to invent a religion based on celebrity endorsements, abstruse hierarchies and personal cash donations, it might look a lot like the Church of Scientology. On most levels it seems a ridiculous organisation. What continues to pique our interest in it is the neurotic – not to say aggressive – air of secrecy under which it operates. How much credence should we give to the stories of violent rage and control surrounding its leader, David Miscavige? And how seriously should we take a religion whose most celebrated adherent is Tom Cruise?

At the start of his new film, which opened on 7 October, Louis Theroux claims to want to find “a more positive side” of the Church, which would be questionable if we did not already know Theroux for the disingenuous documentarist he is. He is not looking for positives at all, and indeed soon scores a major negative when the Scientologists refuse flat to have anything to do with him. He counters by seeking out someone who knows the organisation from the inside. That would be Marty Rathbun, burly one-time enforcer and Mr Fixit of Scientology, now an apostate after he fled its clutches.

With the aid of Marty’s first-hand evidence and a bunch of jobbing actors, Theroux begins filming a series of reconstructions – of Miscavige’s only TV interview, of his ritual intimidation techniques, of his room-wrecking tantrums that left his followers cowering on the floor. This was not a boss to cross – no one even dared to beat him at backgammon.