Defence giant BAE Systems has confirmed that it is cutting almost 3,000 jobs at sites across the country, mainly in its military aircraft division.
The firm ended days of speculation by giving details of a huge redundancy programme, saying it needed to maintain competitiveness.
Ian King, BAE chief executive, said in a statement that the company must "ensure its long-term future".
The biggest job cuts will be at sites in Lancashire and Yorkshire.
BAE employs 40,000 people in the UK and 100,000 worldwide.
The Brough factory, in East Yorkshire, will lose 900 jobs from its 1,300-strong workforce.
At Samlesbury, Lancashire, 565 jobs will go from the 3,970-strong workforce.
At Warton, Lancashire, 843 posts will be lost among 6,537 staff.
Among other plants affected are operations in Dorset, Hampshire, Surrey, and Essex.
Most of the cuts will be made in BAE's military aircraft division, which is being affected by a slowdown in orders for the Eurofighter Typhoon fighter aircraft.
Mr King said: "Some of our major programmes have seen significant changes. The four partner nations in the Typhoon programme have agreed to slow production rates to help ease their budget pressures.
"Whilst this will help extend our production schedule and ensure the production line stays open until we receive anticipated export contracts, it does reduce the workload at a number of our sites.
"Pressure on the US defence budget and top-level programme changes mean the anticipated increase in F-35 production rates will be slower than originally planned, again impacting on our expected workload."
Unite, the biggest union at BAE, said it would meet management on Tuesday "and we will be doing everything we can to mitigate the impact of these cuts."
The union said in a statement: "The government cannot sit on its hands and allow these highly skilled jobs to disappear.