The most mesmerising moment in Going Clear, Alex Gibney’s wrecking-ball job on Scientology, watched so far by 5.5 million Americans, is a clip of leading church executives singing along to a clunking 1980s rock anthem, We Stand Tall. Disciples wave candles and sway in bad knitwear but, by this point in the HBO documentary, we know that the church allegedly blackmails adherents over their sex lives; that it is thuggish to those who question its conduct; that founder L Ron Hubbard was a conman who switched from writing bad science fiction to bad space religion; that his successor “Pope” David Miscavige is portrayed as a psychopath who has repeatedly hit and tortured his staff.

Facebook Twitter Pinterest The film team review Going Clear

So, the clip of Scientologists singing along with Miscavige is sinister, an eerie negative of thousands of North Koreans weeping at the death of mass murderer Kim Jong Il. It feels like brainwashing in action. The North Koreans have an excuse for going along with thought control lest they end up in the gulag; Scientology’s extraordinary achievement, perhaps, is to pull off brainwashing in Florida, in California. But the church’s aggressive lawyers deny all that, and are working hard to prevent the film ever being broadcast in the UK.

In the US, Going Clear has been rapturously received, earning a standing ovation at Sundance. Screen Daily called it “a serious, strange and unsettling account of brainwashing”; Variety deemed it a “powder-keg documentary”; while a BBC reviewer said it had “the scary intensity of a thriller”. But my experience of Scientology has taught me that it is the religion – if it can be called that – that loves to hate, and it certainly hates Going Clear and everyone in it. It says: “Free speech is not a free pass to broadcast or publish false information.” Producer Gibney trades in lies, says the church; the Pulitzer prize-winning author of the film’s source book, Lawrence Wright, is peddling “balderdash”; and the film ends up “glorifying admitted liars expelled as long as three decades ago from the church”.

Facebook Twitter Pinterest John Travolta (pictured with actor Michael Pena) has not watched the film. Photograph: Kevin Winter/Getty Images for CoS

Going Clear paints a jaw-dropping picture of how Hubbard’s 50s trippy-hippy psychobabble, with its space-alien satan, Lord Xenu, has morphed into a multi-billion-dollar corporation; its abuses – physical, psychological, sexual – shielded by that word “religion”; its honour defended by its Hollywood darlings, most famously Tom Cruise and John Travolta. Running the show is Pope Miscavige: a violent thug to the apostates; a living god-ling to the church.

The film opens by crisply demolishing L Ron Hubbard as a charismatic fruitcake rather than the war hero of his official biography. At one point he is pictured applying electrodes to a tomato plant, to prove the validity of his dianetics theory, even with tomatoes. Hana Whitfield, who joined the church in the 1960s, is a thoughtful South African woman who, with a beautiful command of English, describes LRH’s use of violence against adepts who had done wrong; people being thrown off ships; grotesque psychological abuse.

Miscavige and the church deny that he has ever abused anyone either physically or psychologically, and counter-charge that his accusers are guilty of abuse and that is why they were expelled from the church. The church has implied that Whitfield is a money-grabbing and troubled woman with mental health issues, and quotes its former spokesman, Mike Rinder, saying that Whitfield “spreads venom”. Rinder has since left the organisation, and appears as a star witness for the prosecution in Going Clear.

The film tells how Hubbard went on the run from US law enforcement and died in hiding in California in 1986, when Miscavige took over. We see Scientologists wired up to the “e-meter” – two tin cans attached to a dial – which jiggers if you don’t tell the truth in “auditing” sessions. Auditing is Scientology’s version of confession, where the penitent is probed about the “sin” (“What was she wearing?” “What did you do to him?” “What colour was his underwear?”). The sessions are recorded: Going Clear floats the theory that some of Scientology’s celebrity followers may fear leaving, lest the church spill their secrets, especially about their sex lives. You see film of the archive containing those confession secrets and hear the church’s version, that they are sacrosanct.

Facebook Twitter Pinterest Tom Cruise at the official opening of a Scientology church in Madrid, 2004. Photograph: AP/Paul White

Harsh treatment is apparently meted out to those who break ranks. Spanky Taylor used to be the church’s go-between with its star apostle, John Travolta. She talks movingly of how the church put her in its weird dungeon of the mind, the RPF, or Rehabilitation Project Force, because she upset Pope Miscavige, she alleges. The RPF is a prison for Scientology’s equivalent of monks and nuns, where inmates are required to perform humiliating tasks in dire living conditions – allegations the church denies. Taylor sought help from Travolta, who dropped her like a stone, she says. Travolta has not watched the film but his lawyer says that Spanky Taylor is not a reliable source.

Hollywood star recruit Jason Beghe explains “disconnection”: how the church and its members dropped him after he left. Beghe, counters the church, is a “frustrated thespian whose violent off-screen behaviour may not appear on his acting résumé, but is among the credits on his rap sheet”.

Does the church spy on its critics? Marty Rathbun, a one-time inspector general for the church (roughly equivalent to a cardinal), who used to audit Tom Cruise and John Travolta, is shown being harassed by private investigators sent by the church (it calls him a “violent psychopath”). Rinder, who used to run the church’s spying operations against critical journalists, is asked whether the church spied on me when I was making the 2007 BBC Panorama documentary Scientology and Me. “Was he followed?” asks Gibney. “Yes,” says Rinder, “I followed him.”

The documentary tells the story of Miscavige’s alleged violence to members of its holy order, the Sea Org. Rinder is shown standing in the doorway of Scientology’s shop in London’s Tottenham Court Road in 2007, denying to me that he had ever been beaten by Miscavige. Rinder now says that he was lying and that this lie is the reason he left. Several other Sea Org describe being beaten by Miscavige, but Miscavige’s lawyers deny their client has beaten anyone. The church counter-charges that Rinder was abusive and violent while in the church, calling him “the wife beater” – apparently a reference to a 2010 fracas involving Rinder and seven Scientologists, including his ex-wife, after which no one was prosecuted.

American journalist Tony Ortega, creator of a devastating blog about Scientology, explains how the church’s private investigators came for his elderly mother. Scientology’s response is to denigrate him – along with every person in the film. I don’t find this a convincing rebuttal of the evidence of abuse. To be fair, I’ve made two Panorama documentaries on Scientology and written a book on its methods. The church says I am “psychotic, a bigot and a liar” and a church blogger calls me “genuinely evil”.

Producer Alex Gibney has been accused by the church of trading in lies. Photograph: Kevin Winter/Getty Images

Going Clear explores the dark heart of Scientology brilliantly and relentlessly, but it doesn’t seem that the film will be broadcast in the UK any time soon. The church stays in business thanks to three critical factors: firstly, it constricts information about itself by generating fear of horrible libel bills and private investigators’ probing; secondly, in the United States at least, it has the shield afforded by the word religion; thirdly, its celebrity adherents make it look good – or at least less bad – much of the time.

In its goal of preventing a broadcast of Going Clear in the UK, the church has an unlikely ally in Northern Ireland’s libel laws. The 2013 Defamation Act set out a new defence for public-interest journalism on the British mainland: that the plaintiff has to show “serious harm” has been done to it. However, the act has not been made law in Northern Ireland, and Sky Atlantic – which has the UK rights to broadcast the film – cannot cut off the province from its satellite transmissions for this single show.

Peter Robinson, first minister of Northern Ireland and leader of the Democractic Unionist Party, has said: “Publishers and broadcasters who would like to say and do whatever they want and have no consequences for what they say or do ... In some areas, I think there would be a good case for tightening libel laws and defamation laws.”

In the United States, the Internal Revenue Service proclaimed Scientology a tax-exempt religion in 1993. Did the church’s 2,200 lawsuits against the IRS have anything to do with it? It’s a good question – and one that Going Clear raises. In Britain, the Charity Commission has long ruled that Scientology is not a religion. The British Supreme Court ruled last year that Scientologists could get married in their chapel in East Grinstead, but that does not change the church’s status; that you can get married in a British supermarket does not make Tesco a religion. As a government spokesman explained: “The Registrar General [responsible for recording births, marriages and deaths] does not have any remit to determine whether individual organisations should be recognised as religions.” Older religions may have their faults, but they are not pay as you go; ex-Scientologists claim they gave huge amounts of money in a state of “mental kidnap”.

In all of this, the only people who are treated as sacred, it seems, are Scientology’s apostles Cruise and Travolta. One day, perhaps, someone will challenge them about Scientology on the chat-show sofa. But free speech, as Carter-Ruck (the church’s lawyers in Britain) likes to say, is not an unfettered right. Thanks to Scientology’s power and legal muscle, we in the United Kingdom stand crouched.

All of the above, the church denies.

John Sweeney’s book, The Church of Fear, is published by Silvertail books