One of Britain's ballistic missile early warning bases reportedly tracked a UFO, with military chiefs left baffled by the "unknown target".

It has emerged that a secret investigation was ordered in 1981 following the incident at RAF Fylingdales, near Whitby in Yorkshire.

RAF Fylingdales is part of the NORAD missile defence system. Its primary purpose is to give the British and US governments warning of an impending ballistic missile attack, and it was part of the four-minute warning system during the Cold War. But it turns out Soviet missiles aren't all the base can detect.

RAF Group Captain David Todd, the Senior Duty Officer at the base at the time, told The Sun it was not unusual for unknown entities to pop up on the radar at RAF Fylingdales. But one particular incident was different.

He said: "We could not match it up with anything on our computers. And radar tracked it for quite a long time. We had quite a lot of information on it. It appeared to be in Earth’s orbit and we waited for it to come around again but it did not return. So that got us really interested, because people started saying 'ooh, is it a UFO?'."

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