UK manufacturers endured their sharpest decline in five months in September, according to a closely watched survey that highlighted the strain of weak demand, higher costs and ongoing disruption in the automotive sector.

The S&P Global UK manufacturing purchasing managers’ index (PMI) fell to 46.2 in September, down from 47 in August. The figure, in line with economists’ forecasts, signals contraction for the 11th consecutive month as any reading below 50 marks a decline.

Respondents reported a reduction in both domestic orders and export sales. Firms pointed to subdued business sentiment at home, ongoing uncertainty over US tariffs, and higher operating costs as key drags on performance.

Suppliers to the automotive industry also cited production shutdowns at Jaguar Land Rover, which has been struggling with the fallout of a major cyberattack. The disruption added to the challenges facing a sector already under pressure from volatile demand and fragile supply chains.

Rob Dobson, director at S&P Global Market Intelligence, said the survey provided “further worrying news for the health of UK industry”. He warned: “Manufacturers are facing an increasingly challenging environment, with intakes of new business and levels of production hit by weak market sentiment, a dearth of new export work and a high-cost environment exacerbated by tax and labour cost rises. Companies entwined into the autos supply chain are also facing a temporary hit to activity following the cyberattack on JLR.”

Employment in the sector also fell for another month, with companies cutting staff in an effort to offset the rising cost of wages after April’s increase to the minimum wage and higher national insurance contributions.

Matt Swannell, chief economic adviser to the EY Item Club, said some of the weakness might prove temporary. “September’s PMI may be exaggerated by businesses’ concerns over tax rises at the upcoming autumn Budget and temporary factory closures in the automotive sector,” he said. “However, the sector certainly faces weak domestic and external demand as it navigates slowing real income growth, tightening fiscal policy, and a global economy still getting to grips with higher US tariffs.”

Economists said the September figures underline the fragile position of the UK’s industrial base, which has struggled to maintain momentum in the face of both global and domestic headwinds.