LONDON, May 1 (Xinhua) -- As prolonged Brexit delay took its toll on UK factory growth, the country's manufacturing purchasing managers' index (PMI) fell to 53.1 in April, down from March's 13-month high of 55.1, a survey said on Wednesday.

According to the IHS Markit, which compiles the survey, Brexit stock-building continued, albeit to a lesser extent than in the prior survey month.

"Rates of increase in both inventories of inputs and finished products remained historically rapid, despite cooling from the record highs seen in March," said Rob Dobson, director at IHS Markit.

He also noted that the delay to the scheduled Brexit date meant "companies had to ensure levels of key inputs remained sufficiently large to cover as broad a range of outcomes as possible in coming months."

Meanwhile, new export business declined at the second-fastest pace in four-and-a-half years also drove down UK manufacturing PMI.

"As Brexit prevarication continued, overseas clients took to action and found new supply chain routes away from the UK," said Duncan Brock, group director at the Chartered Institute of Procurement and Supply.

Francesco Arcangeli, an economist at Make UK, which represents British manufacturers, said: "Demand from overseas has been hit particularly hard with several overseas customers reducing their British supply chains to divest themselves of their reliance on the UK market."

"This is a clear wake-up call for the government to make sure that time is not wasted in solving the Brexit impasse," he warned.