Quote from buzzy2:
Possibly. By self selection, the most succesful non-american, non-UK currency traders will want to relocate to the country with the best trading hours in the world. That country is the UK. Its special tax regime for non-domiciled individuals doesn't hurt either. France, Spain have similar hours but too much taxes and too many idiots there.
American currency traders tend to be in NYC, just because the biggest banks are headquartered there. UK currency traders are all over the place as long as taxes are zero (Bahamas, MonteCarlo) or "part time residents" at Marbella or Ibiza-Spain