Between 1947 and 1997, reports indicate that the British secret service was investigating the possibility that aliens were visiting Earth.
Two desks were reportedly set up at the Ministry of Defence to take phone calls from the public who were concerned about extraterrestrial activity in the UK.
In something that sounds reminiscent of The X-Files, spies were sometimes sent out to investigate some of these claims - but the desks were closed down in the late 90s amid fears that staff were being distracted from their main duties.
This is exactly what Fox Mulder what stood against, dammit! The truth is out there!
Information about the work the desks did in this time was made public by the Ministry of Defence in the National Archives between 2008 and 2013, after being declassified.
The documents were entitled 'UAP's' (Unidentified Aerial Phenomena) and were released in order to help the military.
They show how during the Cold War, the RAF was interested in learning more about UFOs in attempt to discover new ways of combatting their enemies, how spies were taught how to identify foreign objects, and how to spot aircraft moving like UFOs.
At the time of their release Dr David Clarke, an investigative journalist and university lecturer, told The Sun:
The MoD have been desperately trying to delay the release of these formerly secret and highly sensitive papers for more than a decade.
Even though they have been partly censored they can't conceal the fact the UK military were interested in capturing UFO technology - or what they coyly refer to as 'novel weapon technology'.
And the files reveal they were desperate to capture this technology - wherever it came from - before the Russians or the Chinese got hold of it first.
Although this was 1997, Russia was still regarded as an undefeated enemy with a weapons programme regarded as a threat to the West.
In addition, an article in The Guardian from 2013 highlights how there was still an active UFO hotline in the MoD until 2009.
Cases they logged included a man in Carlisle who claimed he was living with an alien and a man in Cardiff who said that his dog had been abducted by a UFO.
Another file that was included in the National Archives was addressed to the then-prime minister Gordon Brown. It said:
Dear Gordon Brown.
Do you believe the British people have the right to know if your world has been contacted by alien civilisations?
Letters to the Queen and various UK government bodies were also released, most of which complained about the UK government failing to take UFOs seriously.
Upon their release, defence officials told members of the public:
Despite what many people think, and claim, the MoD does not have any expertise or role in respect of UFO/flying saucer matters or the question of the existence or otherwise of extraterrestrial life forms, about which it remains totally open-minded.
They also added that these reports were retained and archived "solely to establish whether what was seen might have some defence significance".
According to The Guardian, around 150 UFOs sightings were received by the MoD between 2000 and 2007, and by 2009 the rate had trebled.
Speaking to The Guardian, David Clarke added:
There is evidence that some people were encouraged to report their observations to the MoD and to the press, which could be a direct result of increased public awareness during the period that the first UFO files were being released by the National Archives.
I believe this demonstrates that UFOs are very much a social phenomenon.
However, in 2009, defence officials stated that no report submitted to them "has revealed any evidence of a potential threat to the United Kingdom" and it was, therefore, an "inappropriate use of defence resources".