BBC reporter John Sweeney was last week seen losing his temper at the end of a sixmonth investigation into scientology. In 1994, The Argus published a damning exposé of the East Grinsteadbased "religion".

Former chief reporter Paul Bracchi, who secretly infiltrated the cult, remembers how its followers relentlessly threatened and pursued him in revenge for criticising their deceptive and manipulative methods. Here Mr Bracchi, who now lives in London, tells the chilling story of how he was stalked and intimidated for months afterwards, even receiving a bullet in the post at The Argus headquarters in Hollingbury.

The voice at the end of the line was trembling. "Is that Mr Bracchi?"

"Yes, it is," I replied. The caller could not have been more relieved. I was supposed to be dead. Someone had started a rumour that I had been killed in a fire.

The same people who had tried to obtain my ex-directory phone number, handed out pamphlets attacking me and dispatched an American private detective - an ex-Los Angeles police officer - to Britain to frighten and smear the source who had helped me expose their activities.

Almost daily threatening letters arrived by fax and post at The Argus where I used to work.

Messages were left on the answer machine at the home of the managing director. Strangers turned up in his village asking questions about him.

And the culprits behind this campaign of intimidation? Step forward the church of scientology.

The Guardian and The Mail have exposed disturbing apparent links between the "church" and the City of London Police.

Last week in a Panorama programme, reporter John Sweeney was seen losing his temper with a scientologist, claiming afterwards that he had been driven over the edge by a concerted campaign of harassment by the group.

I, more than anyone, could understand why.

Sweeney spent six months investigating this so-called religion. I had spent more than a year doing so when stories of my "unfortunate demise" began circulating. By the time you read this article, the church of scientology will no doubt be unleashing its attack dogs - sorry, officials from the Office of Special Affairs - on me again.

The founder of the "religion" - science fiction writer L Ron Hubbard - himself issued directives on how "to handle the Press", including tips on how to get a reporter "fired and discredited". Well, they have tried and failed with me once already.

My first report - The Secrets Of Saint Hill - was published more than ten years ago. Saint Hill is the castle in East Grinstead where the UK headquarters of scientology is based.

The backlash was swift. The first principle of scientology, you see, is "shoot the messenger".

Critics who had contributed to the articles were also targeted. Some of them found Eugene Ingram - who had been branded an "insidious individual" in a court case in the US - on their doorstep.

He "visited" the 77-year-old mother of one of my sources as well as his parents' former home in Staffordshire and his wife's family.

Ingram knew that the man's relatives would not "dish the dirt" on my source. That was not the point.

He just wanted to let me - and everyone else who had helped me - know he was in town. In the parlance of scientology, this is called a "noisy investigation". It has only one purpose - to intimidate.

The real victims of scientology, of course, are not journalists but the parents who have lost sons or daughters to these deluded fanatics.

Their harrowing stories - of which more below - help explain why, in Britain, scientology is recognised neither as a church nor a charity.

It is, in fact, a cult. Scientologists do not like that word so let me repeat it - CULT.

Hubbard, the man who created scientology in 1952, has an unusual CV for a religious and spiritual leader. As well as being a writer, he was a congenital liar. Quite simply a charlatan. That was the view of a High Court judge in 1984, who said Hubbard's theories were "corrupt, sinister and dangerous".

If nothing else, the movement's survival is proof that with money - scientology is worth billions worldwide - you can make some people, even intelligent people, believe almost anything.

Stars such as Tom Cruise and John Travolta have given scientology a profile and showbusiness gloss it simply does not deserve.

Indeed, those who are not familiar with its tactics and history regard scientologists - who are convinced we are all descended from a race of aliens called thetans - as weird, not wicked.

This ignorance has been ruthlessly exploited in Britain. In October, a £24 million scientology centre opened in the heart of London's Square Mile and is now one of 30 "missions" in the country.

Narconon, a scientology group which claims it can get people off drugs, has been invited into schools and colleges. How many teachers and parents know of Narconon's links to the cult?

"Community volunteers" from Saint Hill - could there be a more ironic name for the HQ of a cult? - have been enthusiastically lobbying politicians, police officers and businesses in the City.

The recruitment drive was part of Hubbard's "master plan".

It is spelled out in scientology documents - namely to infiltrate and convert key institutions in society.

The process, so the thinking goes, will eventually lead to a scientology government.

And the "church" has succeeded in cultivating contacts. Up to 20 officers in the City of London Police - from constables to superintendents - have accepted hospitality worth thousands from scientologists.

This included free invitations to a £500-a-head charity dinner where the guest of honour was Tom Cruise.

He is now reported to have bought a home near Saint Hill.

One senior police officer appeared in a church of scientology video and another, Chief Superintendent Kevin Hurley, spoke at the opening of the new "mission" near St Paul's Cathedral, saying the cult was "raising the spiritual wealth of society".

Here's a question for Chief Superintendent Hurley. What kind of church, back in the Seventies, implemented a series of covert operations in America which culminated in the bugging of the US Justice Department?

His ringing endorsement was a triumph for the spin doctors of Saint Hill.

The "church's" cramped, old London base in Tottenham Court Road could not be more different from its magnificent new home in EC4. Could there be a better place to woo influential new friends?

Among them is Sebastien Sainsbury, one of the heirs to the Sainsbury dynasty and European executive director at Lakeshore Capital, which has almost one billion dollars under management.

Scientologists with brochures and leaflets have also descended on investment bank Bridgewell Group, law firms Eversheds, Dechert LLP, Shadbolt and Co and PR consultants Merlin.

The organisation is believed to have a huge expense account to wine and dine contacts but then it can afford to be generous.

Scientology is worth millions in Britain alone and much of its wealth is derived from members paying for courses.

The scientologists, it now emerges, secured relief of £281,344 on the full rates of £351,680 on their London base - a discount of 80 per cent.

The City of London Corporation said the group had been entitled to the huge reduction because it carried out "charitable works". A member of the corporation, Alderman Ian Luder, a partner with leading City accounting and consultancy firm Grant Thornton, spoke at the building's grand opening of the "effective"

help scientology provided for drug users.

In 2003 the Advertising Standards Authority upheld a complaint by the Church of England over unsubstantiated claims that the scientologists' Narconon programme, a combination of vigorous exercise, vitamin therapy, counselling, and sauna sessions to sweat out toxins, had saved "250,000 people from drug abuse".

Scientology's promotional drive is said to be spearheaded by the group's Office of Special Affairs.

Officially, this department is responsible for public relations and legal matters. But OSA operatives are also, it is claimed, scientology's secret service.

Those who undermine the mores and beliefs of scientology - including journalists - must be ruthlessly dealt with.

Hubbard said they were "fair game" and could be "tricked, sued or lied to or destroyed".

That policy, the cult claims, no longer exists. The following account reveals a different story.

A woman, who we shall call Sarah, claims she and her husband, who briefly joined the "church" a few years ago, received death threats after he was wrongly suspected of stealing scientology documents from Saint Hill.

She said: "One day two well-built men in dark suits from Saint Hill arrived at my door. I told them my husband wasn't in but they forced their way in and started rifling through the bookshelves. When my husband returned they bundled him into the car.

"Finally he came back shaking from head to toe. He told me they'd threatened to kill him if he didn't tell him the whereabouts of some stolen documents."

Later, a typed note arrived in the post branding him a "suppressive person" (an enemy of scientology) and informing him he was now fair game. Other notes followed.

Sarah said: "For months after, we had anonymous notes delivered in the post almost daily. They said, You bastard,' You're dead,' Nothing will save you.' It was terribly frightening.

After three months we moved and didn't tell anyone where we were going."

Where does the organisation get the money to hire these goons?

Well, organised religions can be very lucrative - as L Ron Hubbard himself recognised.

Giant photographs of Hubbard adorn the new London headquarters, and his many pronouncements - such as "Man is basically good and it is this basic goodness we want to set free" - are stencilled on walls.

A comment you won't find displayed, though, is the one Hubbard made to an authors' convention before he invented scientology.

"Writing for a penny a word," he said, "is ridiculous. If a man really wants to make a million dollars he should start his own religion."

Basic introductory sessions for scientology cost up to £80. Then there is another course which costs £300, then another.

Indeed, passing all the stages to scientology "enlightenment" - the so-called Bridge To Total Freedom - can cost hundreds of thousands of pounds and has left some people with inheritances frittered away, remortgaged homes and debt.

One elderly couple "lost" their daughter Emily when she married a scientologist in 2002.

Her father said: "My wife noticed it straight away but I tried to dismiss it.

But it became obvious she wasn't the loving, caring daughter we had nurtured.

"We sat her down and tried to discuss my findings and what I saw shocked me to the core. After a few minutes of talking rationally and reasonably to her, Emily erupted, How dare you question my religion?

What you have read is all lies. If you raise this issue one more time I will never contact you.' I think to say she had been brainwashed would be too simplistic.

"This was mind manipulation at the highest level. If she chooses to come back to us we would welcome her with open arms but I can't just live with it. I can't bear the thought of that happening to my beautiful daughter."

What was the phrase Chief Superintendent Hurley used to describe his new neighbours in the City? Ah yes, they were "raising the spiritual wealth of society".

For those, like me, who have faced the wrath of this cult, they are words which ring as hollow as the baloney on which the church of scientology itself is founded.

Do you think scientology is a harmless religion or a sinister cult? Have your say below.