Thousands of jobs in Northern Ireland appear to have been saved after Canadian plane maker Bombardier won a legal battle in the US that has overturned damaging import tariffs on its C-series aircraft.
Politicians and union leaders have welcomed a ruling which stops the US imposing huge 292 per cent import tariffs on planes partly made by British workers. Over a thousand jobs in Belfast depend on the success of the C-Series passenger jet.
UK Prime Minister Theresa May said it was "good news" for UK industry.
Trade union Unite said workers in Northern Ireland "will be breathing a huge sigh of relief".
Bombardier had been widely expected to fail in its bid to overturn a ruling by the US Commerce Department in December that the UK and Canada had given it unfair subsidies.
But the case, centred on a complaint by US rival Boeing, was dismissed by the US International Trade Commission (ITC).
May welcomed the decision, saying, "Bombardier and its innovative workforce play a vital role in the Northern Ireland economy."
On Friday the ITC voted unanimously against Boeing in favour of its Canadian rival Bombardier after Donald Trump's administration had threatened to impose duties of 292 per cent.
The decision defied the expectations of both the British government and trade unions in Northern Ireland. Theresa May spoke with Trump over the dispute at the World Economic Forum in Davos, where the prime minister is reported to have reiterated the importance of Bombardier to the Northern Irish economy.
Boeing had complained to US authorities that the C-series jets were being sold to the US airline Delta below their production cost and had been given illegal subsidies from the UK and Canadian governments. But the commission voted 4-0 in favour of Bombardier against Boeing, which had raised a complaint about the Canadian manufacturer receiving state subsidies.
Boeing had won a ruling in the US that resulted in the imposition of the tariff on Bombardier's jets, which were built for a number of US airlines.
''Today's decision is a victory for innovation, competition and the rule of law. It is also a victory for US airlines and the US travelling public,'' Bombardier said. ''The C-series is the most innovative and efficient new aircraft in a generation. Its development and production represent thousands of jobs in the United States, Canada and the United Kingdom.
''We are extremely proud of our employees, investors and suppliers, who have worked together to bring this remarkable aircraft to the market. 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.''
After the ITC's decision May said, ''I welcome this decision, which is good news for British industry.''
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.''
The Unite union in Northern Ireland said on Friday night that workers were ''jubilant'' over the ruling. Steve Turner, a Unite assistant general secretary, said the victory was a result of political pressure arising from the trade union movement's campaign to save thousands of jobs in Belfast, where Bombardier builds the wings for the C-series jets.