With a civilian population haunted by the Blitz and the Second World War still in the balance, it was one development Winston Churchill could have done without – an incursion into British airspace by an arrow-shaped metallic object feared to contain an invasion force of little green men.

Such was the sensitivity of an alleged UFO sighting by an RAF bomber crew returning to England from a mission over Germany that Churchill ordered it to be covered up with the words: "This event should be immediately classified since it would create mass panic amongst the general population and destroy one's belief in the Church."

This at least was the allegation put to the Ministry of Defence by relatives of a senior British military aide who claimed to have witnessed the cigar-chomping Prime Minister discuss the incident with General Dwight Eisenhower as part of a meeting about a succession of "foo fighter" sightings by Allied air crews in the Second World War. [ INDEPENDENT UK ]