The March figure of 55.1 marked a three-point rise on the month before. This is the 32nd consecutive month that the PMI figure has sat above 50 - a figure that indicates growth in the sector.
Experts have put the unexpected level of growth down to manufacturers stockpiling ahead of Brexit. The survey found that the rate of increase in stocks hit a survey record high for the third month in a row.
Commenting on the results, Rob Dobson, director at IHS Market, said: "Manufacturers are already reporting concerns that future trends could be constrained as inventory positions across the economy are unwound.
"The survey is also picking up signs that EU companies are switching away from sourcing inputs from UK firms as Brexit approaches.
"It looks as if the impact of Brexit preparations, and any missed opportunities and investments during this sustained period of uncertainty, will reverberate through the manufacturing sector for some time to come."
This sentiment was echoed by Helena Sans, head of manufacturing at Barclays, who said: “Encouraging as today’s figures may appear, the true picture of UK manufacturing continues to be obscured by stockpiling, driven by the ongoing Brexit uncertainty, and this pattern looks unlikely to change until manufacturers see some whiff of white smoke above Westminster. New business may have improved from both domestic and export markets but for that to gather momentum and translate into stronger performance, clarity is needed now to avoid the risk of prolonging a more cautious and tentative approach to much-needed investment. Until then, manufacturers need to get on with influencing the factors within their control; retaining a focus on product innovation, controlling costs and remaining flexible in their planning.”
David Atkinson, head of manufacturing SME & Mid Corporate at Lloyds Bank Commercial Banking, added: "The uptick in the PMI reading is encouraging. That said, it’s still difficult to say whether this is indicative of real growth, or whether demand is being temporarily boosted by businesses continuing to stockpile goods. Manufacturers will hope that in the coming months we’ll see a stronger outlook globally or greater certainty at home, which will hopefully prompt increased business investment across the sector.”