The GBP/USD bullish breakout would probably be part of a wave 2 (purple) correction. A break above the 100% Fibonacci level invalidates this wave pattern whereas a reversal below the 100% Fib could confirm it. An immediate break below the support trend line (green) invalidates the wave 2 and indicates a downtrend.
The GBP/USD seems to have completed a bearish ABC zigzag pattern within wave B (green) as expected. The sharp bullish bounce could indicate an ongoing wave 1 (orange), which could push up higher to the resistance zone. There a retracement within wave 2 (orange) might occur and the Fibonaccilevels could act as a support zone.