GBPUSD failed to test 1.6663 resistance and fell down from 1.6623 level. The pair is forming a short term cycle top on 4-hour chart, key support is located at 1.6375, a break below this level will confirm the cycle top, and signal deeper decline to re-test 1.6275 previous low support. Key resistance remains at 1.6663, only rise above this level will suggest that the downtrend from 1.7042 has completed at 1.6275 level already, then further rally could be seen to 1.6800-1.6850 area.