UK Prime Minister Theresa May has expressed discontent over the latest US Department of Commerce’s ruling that seeks to impose taxes on the C Series jets manufactured by Canadian company Bombardier.

May made a commitment to protect 4,200 jobs at Bombardier’s plant in Northern Ireland, reported Reuters.

The plant is engaged in the manufacturing of C Series jets, which are available in 110-130 seat configurations.

Aiming to impose a 219.63% anti-subsidy duty on the Bombardier jets, the US Department of Commerce ruling was passed following a complaint lodged by Boeing accusing Bombardier of receiving undue state subsidies from the UK and Canada.

"This is clearly aimed at eliminating Bombardier’s C Series aircraft from the US market."

The unfair subsidies allegedly helped Bombardier to win a major order, reported BBC. However, Bombardier has denied all the charges.

After the ruling, May tweeted: “Bitterly disappointed by initial Bombardier ruling.

“The government will continue to work with the company to protect vital jobs for Northern Ireland.”

Opposing the decision, Canada’s Foreign Affairs Minister Chrystia Freeland said: “The US Department of Commerce’s preliminary determinations almost always rule in favour of the US complainant.   

“While this is only a preliminary stage in the investigation, and no duties can be imposed until the final investigations are completed, Canada strongly disagrees with the anti-dumping and countervailing duty investigations into imports of Canadian large civil aircraft. This is clearly aimed at eliminating Bombardier’s C Series aircraft from the US market.

“‎Components of the Bombardier C Series are supplied by American companies, directly supporting almost 23,000 well-paying jobs in many US states, including Connecticut, Florida, New Jersey, Washington, New York, Ohio, Kansas, Pennsylvania and Colorado. Boeing’s petition is threatening these US jobs."

Bombardier stated: “The simple truth is that Bombardier created a superior aircraft that is more efficient, more comfortable, and quieter. The C Series serves a market segment not supported by any US manufacturer. Delta [airlines] wants to bring this remarkable new aircraft to the US flying public. Boeing wants to prevent US passengers from realising these benefits, irrespective of the harm that it would cause to the US aerospace industry and the cost to airlines and consumers.”

The penalty will come into effect only when the US International Trade Commission (ITC) rules in favour of Boeing. The final ruling in the case is expected next year.