Aliens Over London?

Several videos have been posted from London England that show several white lighted discs in the sky moving extremely quickly.

Are they aliens?

Some say this is proof!  Some are less apt to jump to the alien theory.  I will say that I'm not sure what to think but these are pretty odd things to see.  Plus with all of the crowd around reacting to the same thing it's hard to imagine it's staged.  But I have been wrong before.  Watch and let us know your thoughts.