BRITAIN'S defence ministry shut down its UFO unit four years ago after concluding that aliens likely did not exist, previously secret files have shown.
The Ministry of Defence closed its hotline in 2009 despite a trebling of reported sightings of UFOs that year, many of them near national landmarks.
National Archives files now made public reveal in a briefing for then defence minister Bob Ainsworth a civil servant said the UFO desk was using up increasing amounts of staff time but had "no valuable defence output".
He wrote in a memo that in more than 50 years, "no UFO sighting reported has ever revealed anything to suggest an extra-terrestrial presence or military threat to the UK".
The files reveal details of sightings recorded in the two years before the UFO desk was disbanded, including some around the Houses of Parliament and Stonehenge.
From 2000 to 2007, the Ministry of Defence received an average of 150 reports a year, but 520 sightings were recorded in the 11 months to November 2009.