Yes, I believe so! I didn't think this at the time. I worked in Leeds and my office was in a very high building (14 floors). Working late one evening, around 7.00pm, I went from my office to an adjacent one, and saw an object I couldn't identify. Shaped like an advertising balloon, but completely plain and silver in colour. It was just hovering. I thought it might be on a tether of some kind, even though I could not see one. As I stood and watched it - it suddenly disappeared. I looked round at the the scene - the building had huge windows and looked out over the city for miles. I spotted the same object again, simply hovering over a different building in a different area of the city. I watched again, and called some colleagues to the window to see it. For a second time, the object just "blinked out" and re-appeared in a different place. This happened five times while we watched. The most interesting thing was the way in which no-one saw the object travel that I remembered distinctly. It moved position without anyone seeing it do so. I stared hard at the cylinder shaped object, not taking my eyes from it, and yet it simply disappeared and then re-appeared somewhere else. It was only later that I decided it must be a UFO. The Cylinder was silver coloured, slightly shiny, with no windows, no lettering, nothing. Completely smooth, no fins, nothing to identify it. The manner in which it moved was the most remarkable thing!