2 spherical UFOs spotted over London, UK

On April 8, 2017, two silver UFO moved across the sky over London, United Kingdom. What is it?

Witness report:

i came home from a fair at approx 4pm looked up at the sky and two silver ball/disc objects came across the clear blue sky, (in a perfect straight line both at a similar speed to each other one behind the other) then i went in my house grabbed my camera (also told my brother want to see something weird, take a look at these outside) then when i pointed the camera up at the objects then one stopped moving and the other one went past it (still at the same flying speed) then that to stopped and came back (as though to see what was going on) the flight line seem to be the same (they were about the length of a plane apart) then carried on going on there journey afterwards, then i came in doors..... some months later i was watching a programe on TV in jan-feb 2018 and they mentioned nasa july 16th 2015 6:30am objects that might have been or resemble these i thought may be the same thing ? (tv show was series 3 episode 8, Nasa the Unexplained files).


, 28th June 2018