The GBP/USD needs to break above the resistance trend line (red) for a bullish breakout and potential continuation of the wave C (blue). A break below the support trend line (blue) indicates a deeper correction within the wave B (blue) pattern.
The GBP/USD bearish decline failed to break the 61.8% Fibonacci support level, which therefore could potentially complete a wave B (blue). But price will need to stay above previous bottom if the current wave 1-2 (green) pattern is able to hold. Otherwise a deeper retracement in wave B (blue) will take place towards the 78.6% Fibonacci retracement.