Defence giant BAE Systems is planning to axe more than 600 jobs and close a historic factory which made tanks for the First World War.
The firm said 330 jobs will be lost through the closure of the site at Newcastle-upon-Tyne, which is currently making Terrier vehicles for the Army. The factory has been a defence manufacturing site since 1847, building a number of ships and employing tens of thousands of workers in its heyday.
Up to 280 jobs will also be lost at three BAE sites in Radway Green, near Crewe, Washington in the North East and Glascoed in South Wales under the proposals, as well as the prospect of 10 job cuts at the firm's head office in Farnborough, Hampshire.
BAE said the proposal to close the Newcastle site at the end of 2013 followed a business review which concluded that there was no prospect of new UK armoured vehicle manufacturing work once production of the Terrier ends next year.
The firm said the proposals now under consultation followed major efficiency improvements and reductions in the amount of ammunitions required by the Ministry of Defence.
Managing director Charlie Blakemore said: "We need to adapt to very challenging market conditions and further reduce our overheads to drive better value for our customers and increase our competitiveness in the export market.
"I know that this is difficult news for employees and we will do all we can to help them through this difficult period and mitigate the proposed job losses wherever possible."
Shadow defence secretary Jim Murphy said: "The country is seeing defence industrial decline on this Government's watch. Ministers must do more to demonstrate they have a long-term plan to stimulate and support the UK-based defence industry."
Rehana Azam, national officer of the GMB union, said: "BAE Systems have a highly experienced and skilled workforce and these job cuts are yet another blow to manufacturing. Representations are being made to MPs to see what can be done to retain skills within BAE Systems and in traditional industrial areas of the UK."
Kevin Rowan, regional secretary of the Northern TUC, said: "The announcement from BAE Systems is a hammer blow to North East manufacturing. Losing so many highly skilled and well paid jobs is devastating for all individuals concerned as well as to our local economy."