David Cameron's "deluded" EU veto could cost UK manufacturers billions of pounds in lost trade, Unite the Union has warned.
Domestic companies will be hit by an anti-British backlash following the Prime Minister's decision not to back a new EU treaty said Unite chief Tony Burke.
Cameron had put the interests of "speculators in the casino of the Square mile" ahead of real manufacturing companies, the assistant general secretary for manufacturing said.
Burke said: "Companies with large skilled workforces across Europe with manufacturing plants in the UK will think twice about further investment in UK manufacturing as we sit, irrelevant on the periphery of Europe."
Cameron's veto will isolate British companies from pivotal economic decisions Unite added.
Businesses who often did business in Euros will now have limited say about fiscal rules governing the currency.
The snub will also create regulatory barriers with mainland Europe, Unite warned.
Burke commented: "Our trading relationships with the EU, the buying and selling our manufactured goods, are built on regulations and standards- all of which will now be jeopardised."
He added: "UK manufacturing and its workers...need stability and a clear strategy for working with member states- instead we will face uncertainty and instability."
Trade with the EU accounts for 50%-60% of export/import business compared to just 17% for the US and China combined, Unite said.
Burke's comments came in a blog on political blogging website Left Foot Forward. See link below: