The latest batch of UFO files released today contain sightings of mysterious lights over the Glastonbury Festival, a "flying saucer" outside Retford town hall and the bizarre story of "Mork and Mindy's" visit to East Dulwich.

Defence experts were called in to examine a 2004 photo of a "flying saucer" taken outside Retford town hall in Nottinghamshire.

The series of images were captured by Alex Birch and having ruled out lens flares and aircraft, he contacted the Ministry of Defence, who sent them to the Defence Geographic and Imagery Intelligence Agency (DGIA) in July 2004.

The photograph was digitally enhanced and the DGIA report stated: "No definitive conclusions can be gathered from evidence submitted, however it may be coincidental that the illuminated plane of the object passes through the centre of the frame, indicating a possible lens anomaly, eg a droplet of moisture."

The files also contain first-hand testimony of retired RAF fighter controller Freddie Wimbledon and retired MoD official Ralph Noyes, on the famous 1956 UFO incident at RAF Lakenheath in Suffolk.

Mr Wimbledon remembers the RAF scrambling fighter planes to intercept a UFO seen on radar and by observers on the ground. The UFO reportedly latched onto to a fighter plane, "following its every move" before speeding off at "terrific speed".

Staff involved were sworn to secrecy, while Mr Noyes recalls being shown gun camera footage of the UFOs taken from aboard the aircraft at a special MoD screening in 1970.

One of the more bizarre tales from the files is the 2003 sighting of "worm-shaped" UFOs "wriggling around in the sky" over East Dulwich in London.

A mother and daughter reported it to the police but according to testimony she later gave to the MoD's UFO desk, the two police constables who attended the scene were joined by two men dressed in "space suits and dark glasses who called themselves Mork and Mindy".

The woman complained of being made "to look foolish". In a letter dated January 21 2003, the woman says "your men have fed us with a lot of rubbish, presumably to make us look foolish and our story unbelievable, which they have succeeded in doing".

Police told the MoD they sent two ordinary PCs to the address but "they could not see anything in the sky and concluded it was possibly a reflection of a star and a street light in her window".

Another report describes mysterious lights seen moving 300ft above the Pyramid stage at the Glastonbury Festival on June 28 2003. There are also details of a UFO sighting over a music festival at Llanfyllin, Wales, in July 2006.

A file also contains a number of sightings reported to the MoD during the summer of 2006, that describe formations of orange lights in the sky. These appear to be observations of Chinese lanterns, released at parties and public events, the experts concluded.

Other incidents include UFOs spotted by the pilot and passengers of an aircraft over the Channel Islands in 2007 and F-16s scrambled to intercept UFOs over Belgium in 1990.