- Video report by ITV News Correspondent Neil Connery
Aircraft manufacturer Bombardier has won a trade case in the United States, overturning a decision to impose tariffs of almost 300% on imports of its C-Series aircraft, safeguarding thousands of jobs which were potentially at risk.
Bombardier is one of Northern Ireland's largest employers and has a major plant in Belfast where it produces the C-Series' wings and employs more than 4,000 people.
Unions said workers at the site would be "breathing a huge sigh of relief" at the news.
The Canadian company had been facing a 292% duty on its exports of planes to the US after American rival Boeing claimed Bombardier had been given unfair state subsidies by the UK and Canada.
However, on Friday the US International Trade Commission (USITC) rejected Boeing's injury claims, saying that Atlanta-based Delta Airlines' order of the C-Series passenger jets does "not injure US industry", and rejected the high duties on the planes.
At a meeting with Donald Trump in Davos on Thursday, Theresa May had raised the issue of Bombardier, which is due to begin delivering an order for up to 125 new jets to Atlanta-based Delta Airlines in 2018.
The Prime Minister said she "welcomed the decision, which is good news for British industry. Bombardier and its innovative workforce play a vital role in the Northern Ireland economy."
Business Secretary Greg Clark added: "The decision by the International Trade Commission confirms what the UK and Canadian Governments working hand in hand has maintained from the outset, that this case is unjustified. We are pleased that the ITC have now recognised this."
Labour leader Jeremy Corbyn also hailed the result in a tweet praising the workers unions.
DUP MP for East Belfast Gavin Robinson said: "This is fantastic news for Bombardierand particularly for the firm's 4,000 workers in Northern Ireland and the many more who form part of the supply chain here.
"This has been a very difficult time for those staff who faced an uncertain future.
"Even in recent days there some pessimism had grown, but Bombardier's greatest strength here in Belfast is the quality of those workers and the product they deliver."
In a statement, Bombardier praised the "victory for innovation, competition, and the rule of law".
They continued: "It is also a victory for US airlines and the US travelling public...
"Its development and production represent thousands of jobs in the United States, Canada, and the United Kingdom...
"With this matter behind us, we are moving full speed ahead with finalising our partnership with Airbus.
"Integration planning is going well and we look forward to delivering the C-Series to the US market so that US airlines and the US flying public can enjoy the many benefits of this remarkable aircraft."
Workers in Northern Ireland reacted with jubilation to the news.
Unite Assistant General Secretary Steve Truner expressed his relief that the USITC overturned the "crippling" tariffs.
"Bombardier workers in Northern Ireland and throughout the supply chain in the UK will be breathing a huge sigh of relief that the International Trade Commission has seen through Boeing's baseless complaint.
"It is a right and just decision which is in no small part down to the tireless campaign by Unite members and shop stewards.
"Unite left no stone unturned in our campaign to protect jobs in Bombardier and the supply chain across the UK.
"When the going got tough Unite did not throw the towel in, our members and shop stewards redoubled their efforts in bringing pressure to bear on politicians in Washington, Westminster, Brussels and Northern Ireland.
"The C-Series is a world beating aircraft made by world class workers.
"There can be no backsliding from the US government on this decision.
"Unite looks forward to continuing to work with Bombardier to secure future sales and investment to ensure a bright future for Northern Ireland workers and the thousands across the UK in the supply chain."
Susan Fitzgerald, Unite regional officer for the union's membership at Bombardier in Northern Ireland, said: "When the story is told of this dispute it will be one of how, in the absence of a genuine effort by politicians and the UK Government, workers themselves had to take the fight on."
She added: "Bombardier itself now must reiterate its commitment to the Northern Ireland workforce and end the outsourcing of jobs to low-cost centres."