The GBPUSD has fallen below its 200 hour moving average (green line in the chart below). That moving average currently comes in at 1.37659. The price is trading at 1.3761 as I type.
The GBPUSD moved higher in the London session and in the process broke above its 100 hour and 100 day moving averages (blue lines near 1.3788). The price high got within about five or six pips of its highs from last week at 1.38337, but could not sustain momentum. The pair tried to hold above the moving averages on the dip in the US session, but broke below and the last hour or so of trading.
Now with the break below the 200 hour moving average, the sellers are making another play for more selling momentum. The low for the day reached in at 1.3756. Move below that level and it opens up the door for potential move toward the 38.2% retracement of the last trend leg higher at 1.3732. That is also near the low from Friday's trade and a swing high going back to October 14.