Unions have reacted with shock after manufacturing giant BAE Systems announced plans to axe almost 1,000 jobs, mainly from its military division.
Officials warned that the job losses in BAE's Military Air Solutions and Insyte (Systems Integrated System Technologies) divisions could be the "tip of the iceberg".
The Confederation of Shipbuilding and Engineering Unions warned that the outcome of the forthcoming strategic defence and security review and the cuts being demanded by the Treasury mean "worrying prospects" for the defence industry.
CSEU general secretary Hugh Scullion said he will be demanding an explanation from BAE.
"Talks will begin locally to attempt to mitigate the planned losses, and if necessary national negotiations will follow," he said.
"The unions will oppose any compulsory redundancies."
"With the forthcoming defence review, these cuts may be the tip of the iceberg. But knee-jerk reactions from employers could make things even worse. Cuts are being demanded before the shape of the defence industry has been decided. The defence industry will suffer more than necessary if employers make poor judgment calls."
Kevin Taylor, the boss of BAE's Military Air Solutions division, said that there could be 212 jobs lost at Brough, in East Yorkshire, 26 job losses at Chadderton, Manchester, 55 jobs lost within the Harrier team at Farnborough, Hampshire, 149 jobs lost at Samlesbury, Lancashire, and 298 jobs lost at Warton, Lancashire.