The Brexit stockpiling boom of early 2019 gave way in May to the steepest downturn in British manufacturing in almost three years as new orders dried up, boding poorly for economic growth in the second quarter, a survey showed on Monday.

The IHS Markit/CIPS UK Manufacturing Purchasing Managers' Index (PMI) fell to 49.4 from 53.1 in April, its lowest level since July 2016 and worse than all forecasts in a Reuters poll of economists that had pointed to a fall to 52.0.

Export orders dropped at the fastest pace since October 2014, the survey showed, reflecting global trade tensions and European businesses diverting supply chains away from Britain because of Brexit uncertainty, the PMI showed.

A separate survey from the 'Make UK' manufacturing organisation published on earlier Monday also suggested EU customers are turning their backs on Britain.

Britain's economy picked up in early 2019, helped by the biggest rise in factory output in 20 years as companies raced to stockpile goods to avoid disruption to supply chains in the run-up to the original March 29 Brexit deadline.