Britain said it was disappointed with a U.S. decision to slap preliminary anti-subsidy duties on Bombardier Inc's CSeries jets which has put around 4,200 jobs at risk in Northern Ireland where the wings are made.
The U.S. Commerce Department on Tuesday imposed a 220 percent duty on the jets after rival Boeing Co claimed the aircraft were unfairly subsidized by Canada.
Britain's Business ministry said it would continue to strongly defend its national interests.
"This is a disappointing interim statement but only the first step in the process," a spokeswoman for the department said.
"Boeing's position in this case is unjustified and frankly not what we would expect of a long-term partner to the UK – as well as damaging the wider global aerospace industry. We will continue to work closely with the Canadian government to encourage all parties to reach a credible resolution as quickly as possible."
