Dreadnought-Class Nuclear-Powered Ballistic Missile Submarines

Dreadnought-class nuclear-armed ballistic missile submarines are being constructed by BAE Systems at its Barrow-in-Furness shipyard in Cumbria, UK, for the UK Royal Navy.

Project Type

Ballistic missile submarine

Programme Partners

Submarine Delivery Agency, BAE Systems and Rolls-Royce


BAE Systems


Royal Navy


Dreadnought-class nuclear-armed ballistic missile submarines are being constructed by BAE Systems at its Barrow-in-Furness shipyard in Cumbria, UK, for the UK Royal Navy.

The UK Government is supporting the Dreadnought ship, submersible, ballistic, nuclear (SSBN) programme, which involves the construction of four Dreadnought submarines. The four SSBNs will be named HMS Dreadnought, HMS Valiant, HMS Warspite and HMS King George VI.

The Trident missile-armed Vanguard submarines will soon reach the end of their lifespan. The Dreadnought-class submarines will replace the four existing Vanguard-class SSBNs to maintain continuous at-sea deterrence (CASD).

The total estimated cost for the Dreadnought programme is approximately £31bn ($47.07bn) and the first submarine is expected to enter service in the 2030s with a service life of a minimum of 30 years.

Dreadnought-class submarine programme details

The programme is based on a white paper published by the UK Ministry of Defence (MoD) in December 2006. The document concluded that the construction of a new class of ballistic missile submarines is the most effective option for achieving and maintaining a nuclear deterrent capability. The parliament backed the white paper conclusions in March 2007.

"The Dreadnought-class submarines will replace the four existing Vanguard-class SSBNs to maintain continuous at-sea deterrence (CASD)."

The MoD then conducted a concept analysis and the assessment phase of the programme. It provided £201m ($291.4m) funding to BAE Systems for the development of the submarine design, including the layout of equipment and systems and manufacturing processes in February 2016. The company was previously awarded two funding packages in 2012 to start initial design and another in 2015 to work on the detailed design.

In July 2016, the House of Commons approved the construction of four Dreadnought-class submarines over the next 15-20 years, enabling the programme to transition to the manufacturing phase. The first metal-cutting for the programme was conducted in October 2016 after the UK Government announced funding of £1.3bn ($1.68bn).

The programme received additional funding of £960m ($1.29bn) from the MoD in May 2018. The Defence Secretary provided £400m ($503.1m) in funding for the programme in December 2018.

A new alliance was formed in April 2018 for delivering the Dreadnought programme. Known as the Dreadnought Alliance, the partnership between the government and industry includes the MoD’s Submarine Delivery Agency (SDA), BAE Systems and Rolls-Royce.

SDA’s alliance covers the supply of equipment for the Strategic Weapon System. BAE Systems will be the designer and shipbuilder, while Rolls-Royce is responsible for designing and manufacturing a nuclear propulsion system.

The contracts for the second phase of the build programme, known as delivery phase 2 (DP2), were signed in May 2018. Expected to run until March 2021, DP2 will continue the construction of HMS Dreadnought and begin the build of the second submarine in the class. The MoD expects to award contracts for DP3 in 2021.

Dreadnought-class submarine design and features

Following the completion, the Dreadnought-class submarine will become the Royal Navy’s largest submarine. It will have a length of 153.6m and displacement of 17,200t. The submarine will be installed with 42.5km-long piping, approximately 13,000 electrical items and more than 20,000 cables.

The submarine will be manned by 130 crew members, including three chefs and a doctor. A designated sickbay will allow the doctor to conduct routine check-ups and distribute medicines.

The submarine will also have separate crew accommodation, toilets and washing facilities for female personnel. A separate study area will be built and gym facilities, including exercise bikes, rowers and weight benches, will also be available.

The vessel will be capable of producing its own oxygen and fresh water. It will feature innovative lighting, simulating day and night.

A new design will be incorporated to make the submarine technologically advanced and safe.

The Dreadnought submarines are planned to be built in 16 blocks, which will be grouped into three major units, including aft, mid and forward.

Dreadnought-class submarines will be equipped with the latest Sonar 2076 system, which will provide the vessel with advanced acoustic detection capability.

The sonar, currently in operation with Astute-class submarines, has a combination of outboard arrays and an inboard processing capacity. The sonars and sensors will increase the crew’s visual and situational awareness.

In addition, the vessels will have a combat system mast that will integrate optical systems, electronic warfare and communications.

Dreadnought-class weapons

The Dreadnought-class submarine will be installed with eight operational missile tubes for launching Trident II D5 missile that can carry nuclear warheads. Four additional tubes will be configured with ballast.

The Trident ballistic missile is a solid-fuel, inertial-guided missile that can carry multiple W76-Mk4/Mk4A or W88-Mk5 re-entry bodies. It has an operational range of 4,000nm (7,360km).

The UK is developing a common missile compartment (CMC) that will accommodate the Trident weapons system in cooperation with the US. The two countries are involved in a programme to extend the Trident II D5 missile’s service life until the early 2060s. The UK is also considering options for the replacement of the existing nuclear warhead, which is expected to be in service until the early 2040s.


The submarine will be powered by Rolls-Royce nuclear propulsion system known as Pressurised Water Reactor 3 (PWR3). The MoD considered three PWR options, including PWR2, PWR2b, and PWR3. The PWR3 propulsion system incorporates a new design and leverages technology to deliver benefits such as simplified operations, longer service life and reduced maintenance costs over the lifecycle.

When compared to the other two options, PWR3 delivers better performance and will help reduce maintenance periods and improve availability. The vessel will be equipped with advanced reactor cores, enabling them to operate for 20 years without the need for refuelling.

Contractors involved

Thales received a £330m ($425.6m) contract from BAE Systems Submarines to provide Sonar 2076 system and combat system mast for the four Dreadnought-class submarines, in February 2020. The contract will create or maintain 520 jobs in manufacturing, engineering and design sectors at Thales’ UK locations, including Templecombe, Cheadle Heath, Crawley and Glasgow.

General Dynamics was contracted to develop a common missile compartment and fire control system for the submarine.

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