The Ministry of Defence has closed its UFO investigation unit, it was revealed today.
A hotline and email address for the public to report strange sights in the skies to the military were shut down on December 1.
The MoD said it had received thousands of reports of UFOs over more than 50 years, but none revealed any evidence of a potential threat to the UK or substantial proof of the existence of extra-terrestrials.
It justified the decision to axe the X Files-style unit by saying there was no "defence value" in investigating the sightings.
The officer who dealt with UFO reports has been moved to another post, saving £44,000 a year.
Past military files on UFOs will continue to be released by the National Archives.
In a statement, the MoD said: "The MoD has no opinion on the existence or otherwise of extra-terrestrial life.
"However, in over 50 years, no UFO report has revealed any evidence of a potential threat to the United Kingdom.
"The MoD has no specific capability for identifying the nature of such sightings. There is no defence benefit in such investigation and it would be an inappropriate use of defence resources."
An MoD spokesman added: "Our resources are focused on the top priority - the frontline in Afghanistan.
"Any legitimate threat to the UK's airspace will spotted by our 24/7 radar checks and dealt with by RAF fighter aircraft."
One UFO expert said the MoD's move seemed a "logical step" at a time when it was having to justify every penny it spent.
Dr David Clarke, a lecturer in journalism at Sheffield Hallam University, said: "I'm obviously disappointed because I think, hidden within all the noise, is interesting material.
"But people have got to be realistic, and when you've got the families of soldiers fighting in Iraq and Afghanistan saying they haven't got the kit they need, collecting reports of funny lights seen in the sky can't be seen as a priority.
"Hopefully in the future it won't be the military that looks into these things - it should be scientists or other people who have got the time to do it."