Replacing the UK's Nuclear Deterrent: Progress of the Dreadnought Class

This briefing paper examines the Dreadnought programme as it advances. It does not examine the Government’s overall nuclear policies, the synergies between the civil and military nuclear sectors, broader programmes within the defence nuclear enterprise that support the deterrent, or the UK’s position on disarmament. Nor does it set out in detail the arguments for and against nuclear weapons.

The decision to replace the nuclear deterrent

In a vote in July 2016 the House of Commons approved the decision to maintain the UK’s nuclear deterrent beyond the early 2030s. After almost a decade of work on the project, that vote subsequently enabled the programme to move forward into its manufacturing phase, which will see the construction of four new Dreadnought class ballistic missile submarines (SSBN) for entry into service from the early 2030s onwards.

What is the Dreadnought programme?

Although commonly referred to as the renewal or replacement of Trident, the Dreadnought programme is about the design, development and manufacture of four new Dreadnought class ballistic missile submarines (SSBN) that will maintain the UK’s nuclear posture of Continuous at Sea Deterrence (CASD).

Under changes introduced in the 2015 Strategic Defence and Security Review (SDSR), the first Dreadnought SSBN is now expected to enter service in the early 2030s and will have a service life of at least 30 years.

Replacement of the Trident II D5 missile itself is not part of the programme. The UK is, however, participating in the US’ current service-life extension programme for the Trident II D5 missile, which will extend the life of the missile potentially to the early 2060s.

Replacement of the nuclear warhead is also not part of the Dreadnought programme. After having deferred a decision on replacement in the 2010 SDSDR, in February 2020 the Government confirmed that a replacement programme is underway. Transition to the new warhead, which will be compatible with the Trident missile system, is expected from the late 2030s onwards.

Delivery of the programme

Recognising that the Dreadnought programme is one of the largest Government investment programmes going forward, the 2015 SDSR made several changes to the structure of the project, specifically with reference to governance and oversight of delivery.

A new Submarine Delivery Agency has been established (as an executive agency of the Ministry of Defence) which will manage the procurement and in-service support of all current and future Royal Navy nuclear submarines, including Dreadnought.

In tandem, the MOD and its two key industrial partners on the Dreadnought programme, BAE Systems and Rolls Royce, have formed a new commercial alliance to jointly deliver the programme.

In 2023, changes were made to the funding arrangements for the nuclear deterrent. All nuclear programmes and expenditure across the MOD have now been brought under one heading: the Defence Nuclear Enterprise (DNE), and ringfenced within the departmental budget, reflecting the increasing interdependence between the nuclear deterrent and the Royal Navy’s other conventional nuclear-powered submarine programmes, including the new conventionally armed AUKUS submarine being developed in conjunction with the US and Australia.

Status of the programme

In May 2022 the MOD awarded contracts for the initial stages of Delivery Phase 3. This phase is expected to last several years and will eventually see the first boat of class, HMS Dreadnought, enter sea trials. Construction of the third boat, HMS Warspite, began in February 2023.

According to the MOD, as of May 2025, the programme remains on schedule.

Jobs and industry

BAE Systems and Rolls Royce are the main industrial partners (prime contractors) in this project.

The MOD estimates that 30,000 jobs across the UK are supported by the Dreadnought programme. The wider Defence Nuclear Enterprise currently supports a total of 47,600 jobs across the UK. That figure is expected to rise to 65,000 by 2030.

Although the MOD has contracted directly with BAE Systems and Rolls Royce for production, an estimated 2,500 suppliers across the UK are working on the Dreadnought programme. BAE Systems estimates that its part of the programme alone will support a £7.5 billion supply chain across 1,500 British companies.

It is unclear how much of the value of the overall programme rests with overseas suppliers. BAE Systems has contracted for some of the specialised high strength steel required for the submarines from a French supplier, which has raised questions as to whether more can be done to promote the British steel industry within MOD programmes. In 2021 the MOD acquired the company Sheffield Forgemasters which, among other things, manufactures specialised steel and components for UK defence, including nuclear reactors.

Cost of Dreadnought

The cost of the Dreadnought programme has been estimated at £31 billion, including inflation over the life of the programme. A £10 billion contingency has also been set aside. As of March 2024, £17.4 billion has been spent on the concept, assessment, and early delivery phases of the project and £3.37 billion of the contingency fund has been accessed so far. The MOD has said that the remainder has been allocated to future years, suggesting that the full £10 billion contingency fund will be spent.

In line with convention, the Dreadnought programme will be funded from the MOD’s core equipment budget. Since 2023 spend on the Defence Nuclear Enterprise (DNE) has been consolidated and ringfenced within the MOD budget.

The annual in-service costs of the deterrent, which prior to 2023 had been estimated at approximately 6% of the defence budget (approximately £3 billion in 2023/24) are now included in that overall DNE spend.