Defence giant BAE Systems plans to cut almost 2,000 jobs this week, according to reports.
Many of the job cuts will affect BAE's Warton Plant in Preston, Lancashire, according to Sky News, and relate predominantly to a slowdown in production of the Eurofighter Typhoon aircraft. The precise number of job cuts, however, is unclear at present.
The cuts could be announced as soon as tomorrow, according to the Financial Times.
BAE employs 34,600 people in the UK, accounting for nearly half of its 83,100 global workforce.
Sources told Sky News that Brexit was not a factor in BAE's decision.
BAE Systems said it "continually reviews its operations to make sure we are performing as effectively and efficiently as possible, delivering our commitments to existing customers and ensuring we are best placed to secure future business".
The firm added: "If and when there are any changes proposed we are committed to communicating with our employees and their representatives first."
Britain's largest union Unite, which is demanding an urgent meeting with BAE, called on the government to "end the uncertainty" for thousands of BAE workers by committing to build the next generation fighter jet in the UK.
Unite assistant general secretary Steve Turner said: "BAE must also come clean on its plans. Unite is demanding urgent discussions with the company. If these job cuts materialise, it will significantly undermine our nation's sovereign defence capability and leave us reliant on foreign powers and foreign companies for the successor to the Typhoon and the defence of the nation."
Turner added: "At the time of Brexit, these are precisely the kind of jobs the UK government should be protecting."