Large Black Orb Filmed over England

In 2008 over England, a very debatable footage surfaced where someone in a secret facility captured incredibly clear footage of an orb trying to hide behind things from its viewing area.

It's extremely clear, even by today's standards, showing details like a line or
parting in the middle, as if it could separate or open itself.

Unlike drones, this orb had no visible propulsion system, suggesting highly
advanced technology.

If you have ideas about what this could be, comment down below.