A bad PMI could see the pound make its way through 1.5200 and more
There's technical support from the broken Nov 2014 resistance line at 1.5230 and that might be all that stands in the way of a bigger move towards the May lows around 1.5170
GBPUSD daily chart
As I said in the quick preview, a minor miss may not move the price that much but it will keep the current bearish pressure on