GBPUSD breaks below 1.6375 key support, suggesting that a short term cycle top has been formed at 1.6623 level on 4-hour chart. Now the fall from 1.6623 is treated as resumption of downtrend. Deeper decline is expected to test 1.6275 previous low support, a break down below this level will signal further fall towards 1.6000 zone. Near term resistance is at 1.6445, as long as this level holds, downtrend from 1.6623 will continue.