Flagship investigation series Panorama has found itself under attack from the Church of Scientology, the controversial cult famously endorsed by Tom Cruise and John Travolta.

After discovering that they were the subjects of an upcoming expose on BBC1, the cult’s leaders launched a dramatic “pre-emptive publicity strike” by turning the cameras on Panorama’s reporters themselves and posting the results on video-sharing website YouTube.

They have also sent out 100,000 DVDs of their findings to MPs, peers, religious leaders and other VIPs.

In one extraordinary clip, the cult’s cameramen filmed top Panorama reporter John Sweeney ‘flipping’ and raging after watching a Scientology video he had seen about psychiatry (a practice that Scientologists disapprove of) during the course of his investigation.

“For an hour and a half they showed me these appalling images,” Sweeney told the Sunday Times, in his defence. “I felt as though I was being brainwashed and that if I didn’t fight it they would have taken over my mind. I’ve reported in Bosnia and I’ve never felt like this, but I am sorry. The moment I lost it I knew I was in the wrong.”

The scene of Sweeney’s shouting match forms the centrepiece of the DVD, which also accuses the BBC of spurning offers of “full and open access” to Scientology’s facilities and deliberately setting out to paint a negative picture of the cult.

Scientologists believe that an evil alien called Xenu ruled the universe 75 million years ago, rounding up creatures from the various galaxies and dumping them in volcanoes on Earth. Their radioactive souls – or Thetans – later became attached to human beings, which, they say, is at the root of our problems today.

The Charity Commission refuses to see Scientology as a religion, and the Church of England has been highly critical of the movement. Scientology’s perceived secrecy was one of the reasons that Panorama decided to investigate it further.

To see the John Sweeney clip, click here.