By Laura CloutSo far this year 150 apparent 'flying saucers' have been reported to police, military bases and the Ministry of Defence, compared to just 135 for the whole of 2007, and 97 the year before.
The figures, released after a request under the Freedom of Information Act, suggest that 2008 will be a bumper year for alien activity.
Malcolm Robinson, founder of the research group Strange Phenomena Investigations said: "Something really bizarre is happening in the skies over the UK.
"I've been dealing in sightings for 30 years and we currently have something very real which mankind cannot explain."
A spokesman for the MoD said as long as sightings presented no threat to British airspace, they were not investigated further. The MoD remained 'open-minded' about aliens, he added.
Earlier this summer, recent sightings were plotted on a map of Britain. They stretched from Liverpool to Dover and from Llanelli to Derby.
Among mysterious flying objects spotted in recent months was a 'glowing' disc spotted above the M5 motorway.
Royal Navy aircraft engineer Michael Madden said he watched the UFO for three minutes before it 'zoomed off' near Weston-super-Mare in Somerset.
Earlier, in Basingstoke, witnesses claimed to have seen a fleet of 12 orange objects in the night sky for half an hour.
And in St Athan in the Vale of Glamorgan a police helicopter crew gave chase to another UFO after it appeared to veer at speed towards their aircraft.
One UFO spotter however was left red-faced after his report of a mysterious flying saucer in South Wales turned out to be nothing more other-worldly than the moon.