While the silvery balls looked like they were part of an early Christmas display, they were not actually related to the holiday. Instead, they were part of an installation called “Four World Set” by artist Tom Shannon that was commissioned by electronic music duo Mount Kimbie:
Article source: https://www.huffingtonpost.co.uk/entry/silver-orbs-break-free-in-london-stormy-weather_uk_63639445e4b04234181cc5e1