The slump in PMI has exposed the government's manufacturing bluff according to Unite, the UK's largest trade union.
Tony Burke Unite assistant general secretary for manufacturing accused Whitehall of being bereft of any industrial strategy.
He said: "The Tory-led government boasted that manufacturing would lead the economic recovery and create jobs for those being made unemployed in the public services."
"Well, the public sector cuts are kicking in, manufacturing is flat lining and the government has no manufacturing plan A - never mind a plan B."
Unite urged Whitehall to increase state aid to restore growth to the sector.
Burke said: "What we need is an interventionist policy, with consistent support for our manufacturing base, not sitting back and watching skilled jobs being put under threat."
"We need a strategic shift in the balance of the economy with a policy of public procurement, support for our key companies and investment in skills."
Excuses over disruption caused by a harsh winter and the Royal Wedding bank holiday did not wash, Burke added.
SME manufacturing businesses needed more help accessing finance from the banks, he warned.