A photographer says he is completely baffled by a mystery object which has appeared in a moody night-time picture of the sea off the north Norfolk coast.

Jeff Harrison was amazed when he came to look at a photo he had taken the previous evening from the clifftops at Happisburgh and spotted a row of lights in the middle-distant sky.

He cannot explain the row of red and white lights but believes they could be part of a very large object.

Mr Harrison, 52, said he had been taking photos for many years and his Canon PowerShot SX20 IS was not a 'nasty, cheap' camera.

He had set it on a chair on the cliffs hoping to capture the moon behind the clouds at about 9.25pm on Tuesday, August 16.

Mr Harrison says he cannot remember seeing anything in the sky through the camera: 'But when I took my eye away I remember, almost in a flash, that there was something there one minute, and then it wasn't. At the time I put it down to my eyes readjusting as I moved away, pressed the button and stood back,' he said.

He claims the object must have been stationary because the camera's exposure time was set at 2.5 seconds and if it had been moving, the lights would have appeared as lines, rather than dots.

And Mr Harrison says he is sure the lights were not from a helicopter as there was no noise of one in the sky and he had since checked operator Bristow's schedule for that evening.

He has made approximate calculations, based on the rough height of the cliff, distance to the horizon and estimated size of ships which are also in the photo, and believes the mystery object was probably about three miles out to sea and only 600 to 700 feet up in the sky. Mr Harrison said: 'If that's right, it must have been pretty big.'

A Wiltshire resident, Mr Harrison is a frequent visitor to Happisburgh where he works with Beach Road resident Bryony Nierop-Reading who runs a tractor-restoration business.

He added: 'This photo has not been messed about with. If the lens was pointing inland you could say that it was light reflected off an object, but it was pointing out to sea. I'm baffled - make of it what you will.'

Heather Dixon, investigations co-ordinator with the volunteer-run British UFO Research Association (BUFORA), said they had received no reports of sightings from Norfolk on August 16. She invited Mr Harrison to contact them with his photo, via the website www.bufora.org.uk, if he wanted to take it further.

Ms Dixon said that, after investigation by BUFORA, about 95pc of sightings were found to have a rational explanation.