UK manufacturers are “gasping for breath” after their worst month for more than six years in June, alarming new figures revealed today.

The Chartered Institute for Procurement & Supply’s worrying new snapshot blamed a “triple whammy” of clients winding down after building up Brexit stockpiles ahead of the original March 29 deadline, weakening domestic markets, and sliding export demand for deepening the pain of a sector accounting for 10% of the economy.

Its activity index, where a score under 50 signals industry contraction, slid to a worse-than-expected 48.0 last month, indicating the weakest growth since February 2013.

The figures also marked the first time since 2013 that the survey has seen sub-50 in successive months — with the prospect of more gloom as firms face prolonged uncertainty ahead of a potential no-deal on October 31.

Cips director Duncan Brock said: “The manufacturing downturn is deepening, with a second month in contraction and production shrinking at the steepest rate for seven years... the sector was left gasping for breath.”

Survey compiler IHS Markit’s other pessimistic findings included business optimism plunging close to all-time lows, and a third successive month of falling employment in manufacturing. Export orders are also falling.

Seamus Nevin, chief economist at manufacturers’ organisation Make UK, said: “Businesses are cutting back on both day-to-day and capital spending with the contraction in output a reflection of growing Brexit uncertainty and worsening global trade winds. Firms are reporting that export demand is falling month-on-month as customers around the world are losing confidence in the future of the UK market.”

The latest figures come after the British Chambers of Commerce warned of a “stagnant” economy in the latest quarter while the Bank of England also cut its growth forecast to zero for the April-June quarter.

Economists predict the damage to the economy could be worse still. Capital Economics’ UK economist Thomas Pugh said: “The upshot is that a hangover from Brexit preparations in the sector will weigh on GDP in Q2. We have pencilled in a 0.1% contraction in Q2 but the purchasing managers’ survey probably increases the risks to the downside.”

Globally the manufacturing picture is also weak. China’s sector saw its worst month since January while activity also slowed in South Korea and Japan.