A UFO was photographed above the A1(M) by a mysterious sky-watcher.

Welwyn Hatfield Times: A close-up of the 'UFO' photographed above the A1(M) earlier this monthA close-up of the 'UFO' photographed above the A1(M) earlier this month (Image: Archant)

The image, of an odd-shaped unidentified flying object, emerged after it was uploaded to YouTube by a user called ZxrAlienWarrior, earlier this month.

The uploader regularly photographs so called ‘chemtrails’ – streaks across the sky caused by aircraft and industrial output.

It is unclear exactly where in the county the object was photographed, but the picture was described as being taken at “around 10pm [on] Monday, July 15 [on the] A1 motorway, Hertfordshire UK.”

The supposed craft was put through a series of visual filters in the two minutes, four seconds clip, and at one point the uploader speculated that it was an alien space craft, similar to those seen in science fiction movies.

The video also featured the words: “Maybe we do have a S.H.A.D.O. Supreme Headquarters Alien Defense Organization.

“Just a thought…! [sic]”

The bizarre video ended with a close up of the mystery celestial body.