SIGHTING REPORT UFO sighting at London

it was flashing light and dark (positive / negative) it had no defined shape as it was spinning. it was spinning so fast clockwise that it created the optical illusion of spinning backwards (like watching a car wheel) and changing shape, a bit like a kaleidascope

it was a bright sunny afternoon without a cloud in the sky it appeared to be a couple of miles up in the sky a moved around at different speeds and in different directions (i.e. not in a straight line like a plane but more like the kind of manoeuvre that only a helicopter could achieve)

i was not the only witness to this Unidentified Flying Object as i was at a Madonna Concert on the pitch at the old Wembley Stadium. i was sitting on the floor with my mate and the people in front of us started looking up and pointing to the sky wondering what was up there. we looked up and couldn't identify it, before long hundreds of people including several policemen were all looking up. i couldn't take my eyes off it for about 20 minutes but eventually got bored with watching it. i looked up later on to see if it was still there but it had gone. i still, to this day, have no rational explanation to what this object could be