The fall runs to a swing high from yesterday
The GBPUSD was trading near the highs for the day, and was trending higher, but the price started to turn, and the last 4 or so hour started to trend more to the downside.
The price fell below an upward sloping trend line at 1.34016, and a swing level at 1.33946 on it's way to a low at 1.33684. That low corresponded with a swing high from yesterday, and was near the close from yesterday at 1.33646. A move below the close from yesterday should solicit more downside momentum with the 38.2% of the move up from the August 24 low at 1.33178. The rising 100 hour MA comes in at 1.33008. That too is in play on more downside selling.
The sellers would keep the most control below the 1.33946 level now. If it can do that, breaking the 1.33684 is an easy target. A move back above that level and the underside of the broken trend line at 1.34064 would keep the buyers more (and firmly) in control.