The UK's manufacturing sector would be hurt if Britain broke away from Brussels after the EU referendum, leading to around 50,000 jobs in the industry being scrapped. This business warning will come from Labour's Alan Johnson as he delivers a major speech on the forthcoming ballot at Airbus in Bristol.

"For UK manufacturing jobs, our EU membership is absolutely critical. Two thirds of British jobs in manufacturing are dependent on demand from Europe," the 'Labour In' chief will argue. "That's two thirds of our manufacturing base reliant on that single market access and Britain's membership of the EU. That's over one and a half million manufacturing jobs here in Britain.

He will add: "And turning specifically to apprentices in the manufacturing industry, and I'm pleased to see some of you here today, around 50,000 apprentices work today in manufacturing apprenticeships that depend on trade linked to our EU membership. That's 50,000 apprenticeships which depend on our EU membership and leaving the EU could put those at risk.

"For each one of those apprentices, gaining skills, earning a good wage and working towards a career, we can't let them down, turn our back on the world and cut British manufacturing and industry off from their largest export market."

But manufacturer John Elliott, chairman and founder of Durham based Ebac, argued: "I believe leaving the EU means our economy will be stronger for both jobs and apprenticeships. This reminds me of the scaremongering that happened when we decided not to join the euro. As I recall there was talk of losing three million jobs if we didn't join."

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Johnson's warning comes just one day before the EEF's national manufacturing conference in London on 24 February. The Business Secretary Sajid Javid, Labour deputy leader Tom Watson, and Tory peer Baroness Karren Brady will be among the speakers.

Matthew Elliot, chief executive of the Vote Leave, campaign will also debate the EU referendum with pro-EU Damian Green MP at the Westminster event. A poll from GfK for the EEF revealed that more than half (61%) of its members wanted the UK to remain inside the EU.

But the survey also revealed that a vast majority (79%) of the pro-EU manufacturers thought David Cameron's renegotiation deal would have little or no bearing on their view.

"Our findings reinforce the fact that companies, particularly those interested in exporting, do not see the point of the UK cutting itself off from its major market," said Terry Scuoler, the chief executive of the EEF.

"More importantly, they reject the idea that the UK faces a straight choice between exporting to the EU or expanding its global reach. They understand that a dynamic and growing economy should and could be doing both and that being part of the EU helps to underpin rather than undermine our global presence and trade ambitions.

"This is not to suggest the EU is perfect – our members are fully aware and frank about the EU's shortcomings. But they also value its benefits and strongly believe that the right way forward is to reform and improve the EU for the benefit of all member states rather than simply walk away."

The EU referendum will be held on 23 June and the latest opinion poll from Survation, of more than 1,000 people between 13 and 20 February, put 'remain' on 48% and 'leave' on 33%.