The Conisholme Wind Turbine "Octopus UFO"

Conisholme is a small village near Louth, in the East Lindsey district of Lincolnshire. South-west of it stands the Fen Farm wind farm, run by Ecotricity. Twenty Enercon E-48 turbines, designed by Norman Foster, rise from the flat fenland. Construction finished on 17 April 2008. Each turbine stands 89 m tall overall, and each blade is 20 m long.

Saturday 3 January 2009. Evening. Dorothy Willows noticed the lights first. "The lights were moving across the sky towards the wind farm. Then I saw a low flying object. It was skimming across the sky towards the turbines." John Harrison looked out of a window toward the wind farm. He saw "a massive ball of light with tentacles going right down to the ground." It looked like an octopus.

Others described bright orange spheres of light streaking toward the farm. The lights looked like balls of flames and seemed joined in formation. Robert Palmer, chairman of East Lindsey District Council, also saw unexplained lights in the sky that evening. One caller reported a low-flying aircraft. Another heard loud banging in the early hours of Sunday. Locals spoke of being woken by a smash at about 4 a.m.

Sunday 4 January. One turbine had lost a 20 m blade entirely. A second blade was bent out of shape. Early reports said no trace of the missing blade had been found. Later accounts placed it at the foot of the tower. Ecotricity called the damage unique. So did the Health and Safety Executive.

Ecotricity founder Dale Vince was candid. "It sounds unbelievable but actually we don't have any explanation at the moment. Give us a few days and if there is a rational explanation we will find it." Ufologist Russ Kellett received more than 30 reports. "This is the second most reports of activity we have ever had." Lincolnshire ufologists searched the area for evidence. Within days the Octopus UFO was international news.

The Ministry of Defence did not investigate. "Unless there is evidence of a potential threat, there is no attempt to identify the nature of each sighting." Ecotricity sent the blade for forensic tests. It put UFOs at the bottom of its probability list, behind lightning, a collision, metal fatigue, or a design, material or maintenance failure.

In February 2009, Enercon's interim report found that the bolts holding the blade to the hub had failed. Vince was clear. "The bolt failure was the effect not the cause of the problem." Enercon kept testing the blade and hub components. Later accounts blame material fatigue in the bolt ring, though a final Enercon report has not been traced.

Then came the fireworks. Emily Bell, the Guardian's director of digital content, said the lights were fireworks their brother Tim bought for their father Peter Bell's 80th birthday party. Bell called it "a medium-sized fireworks display with absolutely no ballistics" and added that "we were laughing that we could have broken the wind turbine."

Fraser McLachlan of the insurer GCube said such failures happen five or six times a year. "Sometimes machines just break." James Oberg suggested ice thrown from one turbine to another. Others floated a meteorite, a stealth drone, a lump of ice and even bats. The fireworks lit the Saturday evening. The bang came around 4 a.m. on Sunday. Some later writers call the two events completely unconnected.

The story lives on in forum threads, retellings and a satirical Register "investigation" staged with toy figures. A later Lincolnshire UFO report brought it up again. Lights were seen that night. A turbine lost a blade. Whether those facts belong to the same story is still the question.