I will leave it up to the viewer to decide what you think has been captured on this video from Shirebrook, Mansfield, Derbyshire, posted mid-January, 2008.
Nottinghamshire, like Derbyshire and South Yorkshire, sits on extensive coal measures, up to 900 metres (3,000 feet) thick and occurring largely in the north of the county. 
Early mining texts from similar areas tell of strange lightballs seen emerging from the ground by prospectors who were exploring mineral seams.
Although much remains unknown about the phenomenon, electrical discharges generated by tectonic stress deep within the earth, is often cited as one theory for the generation of these glowing energy spheres.
Having said all of this, I am not claiming that this is the ultimate answer for the Shirebrook ufo, along with numerous  others which have been seen in these parts down the years; on the contrary, in a percentage of such cases, I am left unhappy about this type of UFO simply being pigeon-holed under the category of Earthlights, (as they have become coined), due to the sometimes high degree of sentience diplayed by the objects... as opposed to just lifeless  lightforms, which is how I would expect such a naturally created mass to be and behave...just dumb!...or are the earthlight-ists telling us something more by default...that our current physics textbooks are wrong, and should be consigned to the dustbin forthwith?