FBU conference voted to take an ambivalent position on an EU referendum yesterday, until members have contributed to the debate.

FBU general secretary Matt Wrack told delegates “the current European project is a bosses’ project” and urged greater accountability for EU officials.

But he said the grouping also offered pros including “lowering of barriers between workers” and the “weakening of nationalism.”

Mr Wrack said: “The European debate is often reduced to a debate about immigration.

“We should be, as a union and as a movement, welcoming migrants to this country.

“Migrant workers complement the UK workforce — they do not substitute for it.”

FBU London secretary Paul Embery moved an unsuccessful amendment seeking to remove a claim that an EU exit for Greece would result in the country being cast into the “political wilderness.”

“As Matt said, the EU is a bosses’ club,” Mr Embery told the hall. “So if we vote to exit, that would suggest we are being cast into the political wilderness.”