Peter Day's UFO Film, A418 near Cuddington, 1973

Thursday, 11 January 1973. Peter Day, a building surveyor, left his home in Moreton, near Thame. He was driving the A418 towards Aylesbury to meet a client at an old water mill near Lower Winchendon. He had a Pacemaker 200 Super 8 camera with him.

Near Cuddington, close to the Oxfordshire border, he noticed something on the northerly horizon. An orange ball of light was moving low across the skyline, "passing on a couple of occasions behind trees at various distances." He later told the Thame Gazette he watched it for several minutes. Then he pulled into a lay-by and began to film. The time was about 09:05.

There was no sound, even with the car window open. On film the light pulsated, "seeming to throb in and out from dim to bright." It was moving away towards the north east, then it was gone. The object, Day said, "moved neither up, down nor sideways" and "was just not there any more." He thought he had filmed for 12 seconds, but the processed film ran to 23.

About three miles away, the assembly bell at Chilton Church of England Primary School was about to ring. Teacher Elizabeth Thompson, driving in from Ickford, saw "a bright orange dome or semi-circle" above the hedges ahead. It was like an "orange bell", slightly flattened underneath, "floating and spinning."

The pupils saw it too. Paula Fox watched it "descend into a clump of trees and then climb up again and move away". Louise Driver saw a ball with a yellowish-orange centre, rotating. Nina Sparks "saw a distinct silvery shape inside the orange". Tracy Perrett saw it "break open into a V shape and slow down" and was the only witness to report a roaring noise.

Kodak processed the colour film and later analysed it. Their finding: "a real object was on the film at some distance from the camera". In the last frame before it vanishes, the trees below the object are smeared out of focus while the hedge stays sharp. Day wondered about a force field as the object left at the speed of light, but Kodak called it "merely camera shake". In 1978, plasma specialists from British universities met at Kodak's North London offices: "Not one of them believed that it depicted ball lightning".

That morning an F-111E of the 20th Tactical Fighter Wing took off from RAF Upper Heyford at 08:56. An engine caught fire. The rudder jammed hard over and the jet circled. At 09:47 Major Bob Kroos and Captain Roger A. Beck ejected, unhurt, and the aircraft came down near North Crawley.

The police had an answer ready: fuel dumped by a military jet in trouble. Day was unconvinced. Fuel, he said, "could hardly burn for that long in the sky".

Jenny Randles investigated for BUFORA. She weighed three options. The events were unrelated, an atmospheric phenomenon had damaged the jet, or the UFO was the jet. She set aside the last because of the steady sideways motion, the silence and the doubts of witnesses who knew F-111s. Ball lightning and a daylight meteor were rejected. So was a helicopter searchlight trial, since the Ministry of Defence had none running in January 1973. Yet the jet was already in trouble when Day filmed. In 1989, Oxfordshire police explained another orange fireball as an Upper Heyford pilot igniting jettisoned fuel. Randles leaned towards a link with the F-111, but left the case open. "Whether it will remain unidentifiable is another matter."