The British government is set to spend an additional $905 million on its nuclear submarine program.

The funding, announced by Defense Secretary Michael Fallon, will help pay for new parts and facilities as well as design work for the Royal Navy submarines that will replace four Vanguard-class submarines built between 1986 and 1999.

"Our nuclear deterrent provides the ultimate guarantee of our security and our way of life," Fallon said. "That's why we are getting on with this investment. This money will support further design work, new infrastructure and the purchase of key parts such as engines and gearboxes, as well as jobs across the U.K."

About $317 million of the new funding will be for new facilities at BAE Systems at Barrow-in-Furness, England, where the submarines will be assembled. There will also be a significant investment in the U.K./U.S. collaboration for the Common Missile Compartment and purchase of key long lead items for the submarines.

The new investment will take the total cost of the assessment phase of the Successor program to nearly $5.5 billion.