BAE Systems has been awarded a £1.3bn contract by the government to deliver the fifth Astute Class submarine.
The contract covers the design and remaining build, test and commissioning activities on Anson, the fifth of seven technologically-advanced submarines in the class.
Manufacturing on the vehicle began in 2010 and Anson is now at an advanced stage of construction and on schedule to be taken out for sea trials in 2020.
Tony Johns, managing director of BAE Systems Submarines, said: "Signing this contract is an important milestone in the Astute programme. This is a hugely complex national endeavour and we are proud of the role we play in helping to protect our nation's interests.
"HMS Astute and HMS Ambush are already demonstrating their world-class capabilities with the Royal Navy, whilst the third submarine in the class, Artful, is continuing with her sea trials.
“The build phase for the fourth, Audacious, is also well advanced, so we continue to make positive progress across the programme."
The defence company employs more than 7,600 people in its Submarines business, which includes those working on the Astute programme.
The programme’s sixth and seventh submarines are under construction in Barrow, Cumbria where the Anson is being built.
The new submarines are powered by a nuclear-reactor and are capable of launching land strikes and have anti-submarine and surface ship warfare capabilities.
The £1.3bn contract was announced by defence minister MP Philip Dunne.
“This £1.3bn contract marks an important step in the progress of the Astute programme,” he said.
“This is a key part of our £166bn plan to ensure that our armed forces have the equipment they need to defend the UK’s interests across the seas, in the skies and on land, both at home and abroad."