Airplanes ofcorse is the most obvious answer, but this was ruled out by the friends that called us to tell us about the light in the sky (because we live so high up they thought we would be able to see it too) they have army/flying experience and they said that it wasn't. It is not shown on the video because the camera run out of memory, but the object dropped to the ground very quickly maybe 1 second? and 15m later it appeared again. lasers perhaps?
I've seen this; I uploaded my own video...it's not as clear as this though. just searched youtube to see if anyone else had seen this before. weird.
saw something similar over London this evening!