Secret MoD documents just released have revealed fears of an alien invasion in the UK and details of a landing of a UFO at Elm Tree Farm, Lacock.

The documents were released as part of the largest ever disclosure of Ministry of Defence files, released last week by the National Archives.

Included is the landing of a domed, circular object five feet in circumference at the Jennings family farm on Monday, September 4, 1967, the same day a further five of these objects were discovered along a line from the Kent coast to the Bristol channel.

It sparked 12 hours of panic at Whitehall before it was revealed as an elaborate student prank contrived by apprentices from Farnborough’s Royal Aircraft Establishment.

However, before the prank was discovered, the Army had blown up the object found at Elm Tree Farm.

The farmer, Dick Jennings, has since died, but his daughter Mary Puntis still lives in Chippenham.

Chief Inspector Frank Dummett, who was called to the farm to deal with the UFO, died in January 2009, but wife Mary still lives in Baydon Lane. She said: “When the police realised it was a prank, Frank took it as a joke.

“He never took himself too seriously. It wasn’t too frightening when they landed but it was curious. Frank thought it was something that had fallen off a plane at first, but when police called the RAF, they found out it had nothing to do with them. The flying saucer was so well made, it looked very realistic.”

When Mr Jennings telephoned the police to tell them a real UFO had landed on his farm, he was asked: “Yes Sir. And are there any little green men walking around it?”

Upon investigating the claim, they discovered he was telling the truth, and Chief Insp Dummett arrived with reinforcements to take charge, quickly followed by Special Branch and CID.

Historian John Keeling, from Essex, is writing a book on the day. Mr Keeling said: “At the time, we were in the middle of the Cold War, and there was real concern that the objects could be of Russian origin.”

“The Chippenham saucer was also the only one that was actually blown up by the Army.” Mr Keeling, whose book, How Big Are Little Green Men?, is asking for anyone in the area with memories of the day to email him: