Thousands of jobs could be at risk in Northern Ireland after a US adjudication against the aircraft manufacturer Bombardier.
America’s Department of Commerce has made a “preliminary finding” that the Canadian company had received unfair state subsidies and sold below cost.
It has now imposed a 219.63% countervailing duty on Bombardier’s new commercial jets.
Image: The plant produces the wings for C-Series airliners
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The trade dispute centres on the sale of 125 C-Series airliners, the wings for which are made in Northern Ireland.
The US International Trade Commission will now consider the case ahead of a final ruling in February.
Noel Gibson, who has worked at the Bombardier factory in East Belfast for 27 years, fears for the future of jobs.
He said: “It is workers who lose out in any dispute and that’s what politicians need to realise, that we suffer when commercial disputes break down.
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“They need to emphasise to Boeing that they need to settle this without putting thousands of jobs at risk.”
Boeing had accused its rival of “price dumping” to win a lucrative contract from the American carrier Delta.
The US aerospace giant claimed each jet cost $33m (£25m) to produce but that Bombardier had sold them for $20m (£15m) each.
Bombardier disputed claims support it had received from the government – £75m from the UK and $1bn (£745m) from Quebec was illegal.
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Theresa May had vowed to do all she could to save the jobs in Northern Ireland and raised the issue with Donald Trump.
Northern Ireland Secretary, James Brokenshire MP, said: “The Prime Minister has conveyed a clear message to the US President on two occasions as to the significance of the Bombardier case to Northern Ireland and to the workers who are employed here.”
Davy Thompson from the Unite union urged the government to reconsider Boeing contracts.
He said the Prime Minister needed to flex her muscle now in the hope of winning trade-deals post-Brexit.
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“Surely at this point in time, she should be standing up for UK workers and hopefully that would set the tone for the future.”
Mrs May’s intervention came at the behest of the Democratic Unionists, on whom her minority government at Westminster relies for support.
Bombardier, the largest employer in Northern Ireland with a staff of 4,100, describes the contract as “critical” to its operations.
Twenty-five percent of the workforce is employed on the C-Series but that number is expected to reach 60% by 2021.
Bombardier workers and supplies contribute an estimated £400m a year to the Northern Ireland economy.