This was filmed in the sky above London, UK on 17th June 2018.
Witness report: Weird, looked like it could be drones/birds/bats…
Long Description of Sighting Report
1. Watching tv in the living room after dinner.
2. My neighbour shouting for me to come outside as they couldn’t really make out what they we seeing from thier angle of the backyard.
3. Drones with LEDs/ Birds/ Bats but the light eminating from them just couldn’t be explained as either.
4. Swarming, rising and falling almost like birds but not.
6. They seemed to merge into the background and disappear.
Author (source: MUFON)