No, the world doesn't resolve around London. It's only that way because of a) the UK's/Europe's long history of commerce over the past 500 years, and b) Timezone, so it can pick up closing Asian business as well as opening to lunchtime US busines.
London also 'closes' at 5pm sharp, ie 90% of the FX desks have gone home. Volume is light after that time as virtually no big corporate business is caried out. An example, if you're Wallmart, BP, Coke, Toyota or Nestle all your big hedging business is done on European time.