An investigation is under way into how a blade was mysteriously torn off a wind turbine amid reports of "strange lights" in the sky.

The turbine at Conisholme in Lincolnshire was left wrecked after the incident.

The Sun quoted residents speculating the damage could have been caused by a UFO.

Wind turbine company Ecotricity said it had never seen anything like it before.

A spokeswoman said: "We're conducting a thorough investigation into what happened. This kind of thing has never happened to us before."

The missing blade was found on the ground beneath the turbine, she said, adding that the company could not speculate on the cause of the damage.

Robert Palmer, 66, leader of East Lindsey District Council and member of Lincolnshire County Council, wants both authorities to investigate what happened. A turkey farmer from North Somercotes, he said he saw a bright white light with an orange edge as he drove close to the turbine on Sunday morning.

He said: "I would be very interested to find out what it was. If we are being looked at by other people, by other planets, it would be interesting to find out why they have chosen this part of the country. It's a rich agricultural part of the country and we have got a concentration of turbines here which may have fascinated them. You just don't know, do you?

"I am not counting it out that it was a UFO. There are things out there that you cannot explain. I would have thought that if it was a UFO, it would have been more sophisticated than to drive in to the turbine. It's fascinating."

The Ministry of Defence said it was not looking into the incident.