Star Trek and The X-Files were among science-fiction TV shows monitored by Scotland Yard over fears they posed a potential threat to national security, it was revealed yesterday.

Nineties TV shows Dark Skies, Roswell, Millennium and the film Lawnmower Man were also watched by the Metropolitan Police Special Branch, according to newly-released files.

Police were concerned British fans of the US shows would kill themselves or turn against society, while they also kept tabs on the shows to protect the country from rioting and cyber-attacks.

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Watched: Star Trek (left) and The X-Files (right) were among science fiction TV shows monitored by Scotland Yard over fears they posed a potential threat to national security

Keeping an eye on things: Roswell (pictured) was also watched by the Metropolitan Police Special Branch

The report compiled in 1997 said that viewers obsessed with the programmes could go into a frenzy triggered by the millennium, leading to anarchy and ‘an act of extreme violence’.

It read: ‘Fuel is added to the fire by television dramas and feature films mostly produced in America. These draw together the various strands of religion, UFOs, conspiracies, and mystic events and put them in an entertaining story line.

‘It is not being suggested that the production companies are intentionally attempting to ferment trouble. However, producers of programmes, including The X-Files, Millennium, Dark Skies and Star Trek, know what psychological buttons to press to excite interest in their products.

‘Obviously, this is not sinister in itself. What is of concern is the devotion certain groups and individuals ascribe to the contents of these programmes.’

The report maintained that as the nineties drew to a close, various groups were showing ‘an unhealthy interest’ in microchip technology and barcodes.

Potential threat to security: The 1992 science fiction film Lawnmower Man was also monitored by police

Horrifying: The hidden dossier was drawn up in response to the 1997 mass suicide by cultists in San Diego known as Heaven’s Gate. Pictured above, medical staff lead a truck carrying some of the 39 bodies

Growing numbers of people imagined microchips could be surgically implanted in their brains to provide immediate screening information, or barcodes stamped on their foreheads ending in 666 - ‘the number of the beast,’ the report said.

The problem is that growing numbers are not treating this as entertainment and finding it impossible to divorce fantasy from reality

Many were also said by the report to be obsessed with conspiracy theories surrounding UFOs, alien abductions, the Vietnam War and the assassination of John F Kennedy.

The hidden dossier - called UFO New Religious Movements and the Millennium - was drawn up in response to the 1997 mass suicide by cultists in San Diego known as Heaven’s Gate.

‘This group like many others drew inspiration from science fiction,’ the report said.

‘Indeed, much of their free time was given to viewing the television programmes Star Trek and The X-Files and then seriously debating which series is superior.’

Scotland Yard was worried many shows were linked to Government conspiracy theories.

‘The problem is that growing numbers are not treating this as entertainment and finding it impossible to divorce fantasy from reality,’ the report warned.

Police: The secret briefing document was obtained from Scotland Yard under the Freedom of Information Act

The secret briefing was obtained under the Freedom of Information Act by Sheffield Hallam University professor David Clarke, while researching his book How UFOs Conquered the World.

Dr Clarke said: ‘The documents show the police and security services were concerned about the export of some new religious movements concerning UFOs and aliens from the USA in the aftermath of the mass suicide by followers of the Heaven’s Gate.

Producers of programmes, including The X-Files, Millennium, Dark Skies and Star Trek, know what psychological buttons to press to excite interest in their products

‘It’s no coincidence this occurred around 1997 - which was the 50th anniversary of the birth of UFOs and the Roswell incident - at a time when the net was buzzing with rumours about aliens and cover-ups.

‘The Special Branch briefing points out the group drew much of its inspiration from science fiction films and movies.

‘Its members spent their time watching Star Trek, The X-Files and reading UFO material online and the authorities were worried that growing numbers of people were finding it difficult to separate fantasy from reality.

‘Their main concern was that the type of extreme outcome seen in the USA might be copied by believers here in the UK.’