The investment covers Delivery Phase 4 of the Dreadnought construction programme and will support hundreds of suppliers and tens of thousands of jobs across Britain. HMS Dreadnought will replace the Vanguard-class submarines that currently conduct the UK’s continuous at-sea deterrent patrols.
The Ministry of Defence expects the four-submarine programme to remain within its £41 billion funding envelope, comprising £31 billion in estimated costs and a £10 billion contingency. It nevertheless acknowledged that the programme continues to face significant pressures and risks because of its scale, technical complexity and the wider economic environment.
Annual spending on Dreadnought reached £3 billion in the financial year ending in March 2026. Total expenditure since the programme began had risen to £23.2 billion by that point.
BAE Systems is building all four submarines at Barrow-in-Furness, while Rolls-Royce Submarines supplies their nuclear reactor plants from Raynesway near Derby. Babcock will provide through-life support once the vessels enter Royal Navy service.
Construction of the fourth and final boat, HMS King George VI, formally began when the first steel was cut in September 2025. The milestone followed continued work on the first three vessels and confirmed the government’s commitment to completing the full class.
Each Dreadnought submarine will carry Trident II D5 ballistic missiles fitted with sovereign British nuclear warheads. Britain acquires rights to missiles from a shared stock maintained at the US Navy’s Kings Bay Submarine Base in Georgia, while the warheads are fitted at HM Naval Base Clyde.
The programme is intended to preserve continuous at-sea deterrence after the Vanguard class leaves service. According to the Defence Nuclear Enterprise 2026 Annual Update to Parliament, the government will also begin defining the requirements for the eventual successor to Dreadnought during the current Parliament.
