Two US fighter planes were scrambled and ordered to shoot down an unidentified flying object (UFO) over the English countryside during the Cold War, according to secret files made public yesterday.
One pilot said he was seconds away from firing 24 rockets at the object, which moved erratically and gave a radar reading like "a flying aircraft carrier".
The pilot, Milton Torres, now 77 and living in Miami, said it spent periods motionless in the sky before reaching estimated speeds of more than 12,000 kph.
After the alert, a shadowy figure told Torres he must never talk about the incident and he kept silent for more than 30 years.
His story was among dozens of UFO sightings in defence ministry files released at the National Archives in London.
Torres described how he scrambled his F-86 D Sabre jet in calm weather from the Royal Air Force base at Manston, Kent in May 1957.
"The order came to fire a salvo of rockets at the UFO.
"I had a lock-on that had the proportions of a flying aircraft carrier," he added.
"The larger the airplane, the easier the lock-on. This blip almost locked itself."
At the last moment, the object disappeared from the radar screen and the high-speed chase was called off.
There is no explanation for the incident in the documents.