Regardless of Brexit or not in my opinion I believe that GBP has been in a downtrend since 2014 and would have met the current value of GBPUSD0.47% at what it is now, sooner or later. Brexit just happened to help reach the goal faster. I believe there is more short side to GBPUSD0.47% in the long term where we can meet our all time low before going back up.
