The Dreadnought class will replace the Vanguard class submarines from 2028 onwards and will host the United Kingdom’s nuclear deterrent.

The United Kingdom’s nuclear deterrent today is hosted by the Vanguard Class submarine. The class has been purpose-built as a nuclear powered ballistic missile carrier, incorporating a selection of successful design features from other British submarines. Due to this it is quite unlike its predecessor, itself an adaptation of the Valiant class.

The Vanguards were designed and built by Vickers Shipbuilding and Engineering Limited at Barrow-in-Furness. They are by far the largest submarines ever manufactured in the United Kingdom and the third largest unit in the Royal Navy. A special manufacturing facility had to be purpose-built at Barrow for their construction.

The Vanguard Class submarines are larger than the Resolution Class they replaced mainly due to the need to accommodate the Trident D5 missile. However, the crew complement of a Vanguard Class boat is smaller – 132 officers and men compared to a Polaris submarine’s crew of 149. The newer boats include a number of improvements over previous British submarines, including a new design of nuclear propulsion system and a new tactical weapon system for self-defence purposes both before and after missile launch. The 16 tube missile compartment is based on the design of the 24 tube system used by the United States Navy’s Ohio Class Trident submarines.

In August 2003 it was ten years since the lead boat, HMS Vanguard had commissioned. In 2005 she returned to service after completing the first of the two Long Overhaul Periods (the first including a nuclear refuelling) planned during her service life. She was designed with a twenty-five year hull life and thus was expected to require replacement by about 2019, but a less demanding operational profile and deployment cycle than originally anticipated will allow her projected service life to be extended to 2024 if required, and it seems like it will be.

As things stand today, the Astute project currently seems likely to end with the completion and delivery of the seventh hunter-killer around 2019, while the first Vanguard replacement is required in 2021.

Government approved initial gate for the Dreadnought submarine programme to replace the the Vanguard class in May 2011.

While details remain sketchy at best regarding the Dreadnought class, one of the key features the new boats will have is a Common Missile Compartment (CMC). CMC aims to define the missile tubes and accompanying systems that would be used to launch new ballistic missiles, successors to the current Trident II/ D5 missile fleet used by the USA and Britain.

As key trends like cheaper sensors, increasing autonomy and artificial intelligence march onward, the next 40 years will see big changes in the underwater environment. SSBNs will need the flexibility to adapt to these changes if they intend to survive.

For the USA and Britain, the CMC needs to be part of that adaptation. Key options under consideration include a widened diameter for each tube from 2.21m – 3.04m, and the potential for flexibility beyond nuclear missiles, this would provide incredible future-proofing while delivery a (to some unwise), multirole capability.

The British government took the first steps in 2006 towards a joint US-UK missile compartment and the project was launched in 2008, initial gate approval for Britain’s ‘Successor’ project followed in 2011. Other contracts have followed, covering design and even the new kind of nuclear reactor the submarines are expected to use.

There is a precedent for this in the United States, the Virginia Class Block III fast attack submarine replaced their 12 vertical-launch cruise missile tubes with 2 Common Weapon Launcher (CWL). The size of those CWLs allows Virginia Class Block III submarines to launch cruise missiles, UAVs, UUVs, and more from their tubes.

British and American collaboration will also benefit and informs the Dreadnought class missile capability. The 2010 Strategic Defence and Security Review stated the submarine will have eight operational missiles, carrying no more than 40 operational warheads between them. Furthermore, an important feature of the collaboration between the UK and the US has been collaboration between the UK and the US on the new and advanced PWR-3 pressurised water reactor nuclear.

PWR-3, representing the third generation of British pressurised water reactors, builds on cutting edge nuclear propulsion research undertaken by the MoD and Rolls-Royce in the last few decades and is rumoured to be at a very advanced stage of development.

The exact nature of the UK’s industrial access to US reactor technology remains largely unknown in the public domain, the Royal Institution of Naval Architects reported previously that it is likely that the UK has been given a good look at the S9G reactor design that equips the US Navy’s Virginia Class submarines.

Back to the missile compartments, there is no question that the future Common Missile Compartment will be built around the nuclear deterrence mission as its primary focus. That is unlikely to be its sole use, however, and it would not be surprising if some of those other potential uses ended up influencing the CMC’s design. As is the case with a force more focused on multi role capability, versatility is key. Industry is unsurprisingly quiet on the specifics of the engineering and technology but industry has given some intriguing glimpses at what we may see in the water, one day.



According to BAE, the lead partner for the Dreadnought programme, work on the concept design phase had been ongoing since 2007, but this has now completed, a submarine design has been selected and the build has started.

Tony Johns, Managing Director of BAE Systems Submarines said:

“This additional financial investment by the MOD is an expression of confidence in our ability to build these sophisticated vessels. We have been designing the new class of submarine for more than five years and thanks to the maturity of our design, we’re now in a position to start production on the date we set back in 2011.

This is a terrific achievement and I pay tribute to all those who have made this possible.”



With regards to cost, it’s expected that the Dreadnought submarines and their infrastructure will cost around £15 billion. This can be broken down as such:

£0.25 billion to participate in the Trident D5 missile life extension programme.

£11 billion for a class of four new submarines.

£2 billion for possible refurbishing of the warheads.

£2–3 billion for infrastructure (spent over 30 years).

“Of course, the deterrent is not cheap – no major equipment programme is. But our current nuclear weapons capability costs on average around 5-6 per cent of the current defence budget.”

– David Cameron, the Telegraph, 4 April 2013

According to a series of statements made in Parliament by ministers of the MoD, the annual operating costs of the Trident programme will indeed be around 5 to 6 per cent of the defence budget.

This means that the replacement submarines will have a running cost of around £2 billion per year.

Estimates of the long term costs of big capital spends are notoriously hard to predict and can often fall or rise drastically. The costs associated with the programme are comparable to the procurement costs of major weapons systems such as Typhoon or Lightning aircraft.

The programme already employs more than 2,600 people across MoD and industry, including 1,800 at BAE Systems. Thousands more will be employed in the supply chain with an average of 7,800 people expected to be working on Dreadnought each year throughout the duration of the programme.

At peak, in the early 2020s, BAE Systems anticipates employing more than 5,000 people on the Dreadnought programme.