London, September 13 : A sexagenarian RAF expert claims that the Ministry of Defence in Britain asked him to keep quiet after he tracked a whole fleet of "spaceships" on military radar in 1971.
Sixty Wing Commander Alan Turner, 64, who was a chief operator of the RAF's radar system for 29 years, said that all his colleagues were surprised to see 35 super-fast vessels appear on their screens.
He said that the craft were equally spaced and shot from 3,000ft to 60,000ft at almost 300mph.
He revealed that every UFO would suddenly vanish from radar after a few seconds, and be replaced by an identical vessel moments later.
According to him, six military radars and operators at Heathrow spotted the UFOs east of Salisbury Plain, and filed reports on the unexplained phenomenon in 1971.
The RAF chief even drew a map charting their flight in between key sites like RAF Lyneham, Wilts, and the aircraft navigation transmitter at Brookmans Park, Herts.
However, staff members were instructed to "never speak about the incident again", when the Ministry of Defence visited the RAF three days later.
"UFOs are a fact - I tracked them on military radar units. What I saw defied all logic and was, quite frankly, extraordinary. It wasn't just me," British tabloid The Sun quoted Turner, who retired from the RAF in 1995, as saying.
"More than 30 pairs of eyes of RAF staff and radar operators at Heathrow Airport witnessed the same thing. It's arrogant to believe that we're the only ones in this universe," he added.
Turner, who was a radar supervisor at the now disused RAF Sopley base, Dorset, in 1971, further said: "I instantly knew this wasn't a convoy of military planes. The only craft with that rate of climb were supersonic lightning aircraft but they wouldn't have been able to hold such a perfect formation. They also make a lot of noise. No one heard a thing on the night in question."
Turner, awarded an MBE in 1984, is guest speaker at the Close Encounters conference in Pontefract, West Yorks, next month.
Philip Mantle, of UFO Data magazine, said: "His testimony is remarkable."