|Some of the redundancies will be made at BAE's plant in Warton, Lancashire|
The FTSE 100 company said the redundancies - across military, maritime and intelligence services - would be part of moves to streamline the business with a renewed focus on technology.
Unions reacted with anger - describing the company as "short sighted" and accusing the Government of ceding control of UK defence manufacturing to factories overseas.
As Sky News exclusively reported on Monday , BAE confirmed the biggest cutbacks would fall in its military air business amid sluggish orders for its Eurofighter Typhoon and Hawk aircraft - forcing production to be slowed down.
It said 1,400 jobs would go across five sites over the next three years. The Warton and Samlesbury plants in Lancashire - where the Typhoon is assembled - will bear the brunt of the losses, alongside its Brough factory in east Yorkshire.
Operations in Portsmouth will be worst affected by plans to cut 375 staff from maritime servicing and support.
|The Typhoon is assembled at BAE's Warton and Samlesbury plants|
The news was announced just three months after the company got a new chief executive, following the retirement of Ian King, and it announced a potential deal with Qatar for 24 Typhoons and six Hawks.
The Typhoon is assembled at BAE's Warton and Samlesbury plants
Charles Woodburn said: "The organisational changes we are announcing today accelerate our evolution to a more streamlined, de-layered organisation, with a sharper competitive edge and a renewed focus on technology.
"These actions will further strengthen our company as we deliver our strategy in a changing environment."
Unite assistant general secretary, Steve Turner, said the job cuts "would devastate communities across the UK and the hope of a decent future they give to future generations".
He added: "These are world class workers with years of training and expertise on which an additional four jobs rely upon in the supply chain.
"The UK Government must take back control of our nation's defence and with it, play its part in supporting UK defence manufacturing jobs.
"Too much taxpayers' money earmarked for defence spending is going to factories overseas. By 2020, 25p of every pound spent on UK defence spending will find its way to American factories alone rather than being spent here in the UK.
"This state of affairs is not only hollowing out Britain's sovereign defence capability and British manufacturing, but leaving the nation's defence exposed to the whim of foreign powers and corporate interests."
Labour echoed that sentiment and called on ministers to bring forward spending on defence projects - such as replacing the ageing Red Arrows Hawk aircraft.
A government spokesman said: "BAE Systems have taken this decision as a result of internal restructuring. It is clearly a concerning time for their workers and the Government stands ready to support those affected.
"Our MoD spent £3.7bn with BAE last year, and we also continually bang the drum for our world-leading defence industry right across the globe, supporting companies like BAE in securing contracts for UK-made equipment."