Was letting the dog out into the garden for the toilet late at night. i was up late because i work nightshift and was my night off, i had been watching marco polo on netflix and was totally sober and wide awake. i was standing in the kitchen doorway admiring the moon as although it was a clear night the moon had a thin layer of cloud covering it. the cloud was so thin you could still see the moon clearly through it and the light of the moon lit up the cloud a bright white against the black of the sky. i was also watching a distant passenger jet higher up with its lights blinking when all of a sudden a large dark perfectly oval rugby ball shape flew past/through the bright white cloud just above the moon and dissapeared into the blackness of night on the other side of the cloud. it was black with no lights and made no sound it moved in a straight line and it had taken about four to five seconds to pass through the cloud. its hard to say what size it was as dont know how far up it was. it was above the cloud at least and from my point of view it was about a third of the size of the moon and much much bigger than the passenger jet. when i saw it i had to do a double take. i my life have seen many strange lights in the sky that could easily be explained away and have always laughed at the notion of ufos. but i sure as heck believe in them now. unless there are some really weird shaped aircraft flying around at night without lights on that is. i stood watching for a whle afterwards but nothing else happened