The UK submarine force is also being modernized. The Royal Navy maintains a fleet of ten nuclear-powered submarines, currently comprised of three types. The four Vanguard Class Strategic Ballistic Missile Submarines are carrying the Trident II D5 intercontinental ballistic missiles. These submarines are set for replacement in ten years, by the Dreadnought class, currently in preliminary design. About half of the £3.3 billion budget cleared Parliament for the program has been awarded.
The funding will enable BAE Systems to develop the design of the submarine, including the layout of equipment and systems, and to develop manufacturing processes, including the production of early prototypes. The new submarine will replace the Vanguard class subs in the 2030s.
Three Astute submarines and three Trafalgar class attack submarines make the conventional force. Both classes are nuclear powered with new Astute subs gradually replacing the aging Trafalgars. The construction of the fifth and sixth Astute class attack submarines is ongoing. In April MOD concluded negotiation of the contract to build the Agamemnon, the sixth boat, at the cost of £1.4 billion. As its sister subs, the submarine is built at the BAE Systems in Barrow-in-Furness, Cumbria. Construction of the Agamemnon is expected to complete in 2022; It will be followed by the seventh and final submarine of the class.