BAE employs 34,600 people in the United Kingdom - almost half of its global workforce.
The jobs lost are largely at five sites over three years, including Warton and Samlesbury in Lancashire that make the Eurofighter Typhoon jet.
He added: "I recognise this will be hard news for some of our employees and we are committed to do everything we can to support those affected". However, he said he remained confident about future orders for the aircraft.
In a statement, the company said that the move would help "boost competitiveness, accelerate technology innovation and improve operational excellence from a more streamlined business". These devastatingly short sighted cuts will harm communities, jobs and skills.
BAE is facing an order gap for the Typhoon so wants to slow production before an expected order from Qatar.
Sources have claimed Brexit is "not a factor" in the decision but it was expected to be raised at a meeting between business leaders and Theresa May yesterday.
Speculation that the cuts would be announced already emerged on Monday, but Tuesday's figure is greater than many had anticipated.
"The Prime Minister must forge trade deals with overseas partner countries, as well as delivering a cast-iron commitment now to build the next generation fighter planes", he said.
She said the government was working with BAE to ensure compulsory redundancies were kept to a minimum, and to secure more orders from overseas.
For months the company has been grappling with a slowdown in orders for the Eurofighter Typhoons. A potentially large order from Saudi Arabia is still under negotiation.
BAE is in a slightly stronger position on the Typhoon, where it is assembling further aircraft for the UK Royal Air Force and the remaining 10 examples for Oman to complete its 12-strong order.
Unite estimates that by 2020, a quarter of the UK's defence budget will be spent buying military platforms from companies such as Boeing and Lockheed Martin.