'Scientologists believe the Holocaust was planned and carried out by psychiatrists'

Five years on from the Panorama outburst that resulted in a worldwide viral viewing, John Sweeney has written a book on the dangers of the cult religion

The Church of Scientology is a cult whose core aim is to fight a space alien Satan that's brainwashed the rest of us. The Church fights the world's insanity, its celebrity followers argue, and people who tell you differently are bigots. So who's right?

Lawrence Wright is a Pulitzer Prize-winning reporter who has written what promises to be a great book on Scientology. Going Clear is due to be published everywhere on 17 January – except Britain. Just before Christmas, Transworld, Wright's British publishers, pulled it, leading to questions about whether it had fallen to the Church's reputation for going after its detractors and Britain's libel laws.

Wright had a huge advance negotiated by über-agent Andrew Wylie, publishers around the world primed to publish on the same day, a reported print run of 150,000 in the US and a team of researchers checking every fact. He will have things to say in his book that readers – especially young people, the audience the Church seeks to recruit – may think they have a right to know. American readers will learn all, while Wright's potential British readers will have no book to buy.

By way of explanation, Transworld's publicity director Patsy Irwin said: "The legal advice that we received was that some of the content of the book was not robust enough for the UK market, that an edited version would not fit with our schedule and the decision was made internally not to publish."

Five years ago I lost my cool, to say the least, during an interview with the Church's senior spokesman Tommy Davis in a BBC Panorama called "Scientology & Me". I apologised then and I apologise now for that tirade, and the footage of which went viral around the world. But in the intervening five years I have remained gravely troubled by the power of the Scientologist Church to intimidate critics and to maintain a hold over its adepts which some say is a kind of mental enslavement. The Church, for its part, says that I am a psychopath – one Scientology blog says: "John Sweeney is genuinely evil."

Five years on from my very public meltdown, I've written a book, called The Church of Fear: Inside the Weird World of Scientology, which is published today. Getting the book out has not been easy. My publisher is a bloke with a dog I met in a park. We are going ahead with our book, come hell or high water, because dog bloke and I feel passionately that this story is in the public interest and it needs to be told.

The reason I went with dog bloke is simple. It wasn't the lavishness of the advance – a pint and a packet of crisps. It was because every single major publisher in Britain said "no" to my book. The reason some gave was legal risk. The Church's lawyers in Britain, Carter-Ruck, libel specialists beloved of celebrities, politicians and major corporations, have said: "Free speech is not an unfettered right." You can say that again.

I don't necessarily blame the publishers. A combination of this expensive legal team and Britain's libel laws make publishing criticism of Scientology in this country a daunting task. In America, the legal test for libel is that the plaintiff has to prove the defendant has actual malice to win. In Britain, our laws – under which the defendant has to prove the truth of what he is saying – have prompted repeated calls for change, with many arguing that they stifle free speech. A reform Bill, which critics say is too weak, is currently crawling through the House of Lords.

Publishers might have had other reasons for not wanting my book in the first place, but it was legal concerns, at least in part, that prompted Transworld to cancel their release of Lawrence Wright's much-anticipated work, having previously agreed to do so. While the book launch will go ahead in other countries, perhaps they felt they just couldn't take on Scientology in the UK.

Dog bloke and I think we can. A word about him. His name is Humfrey Hunter, he is a literary agent turned publisher, his company is Silvertail Books and his father and grandmother were German Jewish psychiatrists. Together, his dad and granny wrote the book that set out the medical evidence that Mad King George suffered from porphyry, the basis for Alan Bennett's The Madness of King George.

I lost my temper with Tommy Davis inside the brainwashing section of the Church's exhibition on psychiatry, "The Industry of Death". Scientologists believe that psychiatry is Nazi pseudoscience. They believe that the Holocaust was planned and carried out by psychiatrists. If you are doing a book about Scientology, then you cannot do better than having the son and grandson of two German-Jewish psychiatrists as your publisher. You don't need capital to publish a book on Scientology – you need courage.

Standing shoulder to shoulder with us are a number of ex-members of the Church who possess that quality. They would, they say, be willing to give evidence in our defence were the Church to sue us: Mike Rinder, former head of the Office of Special Affairs, who quit the Church in 2007 after goading me alongside Tommy; Marc Headley, who says he was audited by Tom Cruise and came with me on my visit to the Church's Trementina Base in New Mexico, where the Church has buried Founder L Ron Hubbard's lectures on discs of gold in an H-bomb-proof vault; Amy Scobee, former head of the Church's Celebrity Centre, and more.

But perhaps the Scientologists will do no more than threaten and bluster. Carter-Ruck were first hired in 2007, Mike Rinder told me, to prepare a case against Panorama. But at the last moment, the Church's Chairman of the Board, David Miscavige (Tom Cruise's best man at his wedding to Katie Holmes and a man accused of violence by several ex-Scientologists, a charge he and the Church flatly deny) pulled out. If they go ahead this time, it should make for an incredibly interesting court case.

"The Church of Fear: Inside the Weird World of Scientology" is published by Silvertail Books and is available in paperback (£12.99) and e-book £3.20 on amazon.co.uk