"Look out…look out" - the harrowing words as a jet pilot with 57 passengers on board reports seeing a UFO.

Italian captain Achille Zaghetti shouted to his co-pilot as they narrowly missed a suspected 'UFO' while flying over Kent.

It was 1991 when the flight over Lydd, Romney Marsh experienced what seemed like a missile heading towards it.

The dramatic near-miss is listed in the latest UFO files released by the Ministry of Defence, which is now accessible for the first time to the public via The National Archives.

To this day the sighting remains a mystery.

Dr David Clarke, UFO Expert, said: “It is the most impressive UFO incident ever been reported and investigated by the MOD.”

Capt Zaghetti was flying back from Milan to Heathrow at 22,200ft with 57 passengers on board on April 21, 1991 when he saw a light brown flying object, three metres long, cross their path.

In an air traffic incident report form he wrote:“During descent I saw for about three to four seconds a flying object, very similar to a missile.

“It was higher than us, about 1,000ft (higher). At once I said: ‘look out – look out' to my co-pilot, who looked out and saw what I had seen. As soon as the object crossed us I asked the operator if he saw something on his screen and he answered. ‘I see an unknown target 10 N.M behind you.’”

~Listen: David Clarke tells of the mystery that still surrounds the 1991 sighting>>>

The near collision was immediately investigated by the Civil Aviation Authority but in a public statement at the time it said extensive inquiries failed to provide any evidence of what the sighting may have been.

Mr Clarke believes these types of sightings are happening more regularly but pilots are too scared to say anything for fear of losing their jobs.

He said: “There is a culture of not reporting incidents like these as the subject as a loony image.

“A lot more of these sightings are happening but pilots are worried about their careers and don’t want to be come across as flying saucer nutters.”

For more information visit www.nationalarchives.gov.uk/ufos

UFOs were also investigated in other parts of the county.

A woman in April 1990 who was in her car at a crossroads in Broadstairs saw a bright green disc, shaped like a coin with white light on one side, which made her engine and lights cut out on her car.

In April 1990 an observer saw a straight black line that moved slowly with plumes of smoke recorded as being similar to a F-117A Stealth fighter plane off the coast of Deal.

In November 1988, at a mobile caravan park near Tenterden Road, Biddenden, a walker saw a bright oval object in the skies, which had a very bright red light in the centre and made a deep hum. It caused telephone wires to be dead when she attempted to make a call from the kiosk.