The programme to replace the UK’s nuclear deterrent has been underway since 2006.

At potentially £41 billion, it is one of the Government’s largest capital projects, while defence budgets remain constrained. Questions also continue to be asked about the rationale for the deterrent and whether its replacement contravenes the UK’s international legal obligations.

The next major decision is whether to replace the current nuclear warhead, which is expected to retire in the late 2030s. To meet that deadline a decision needs to be taken in this Parliament.

The Dreadnought programme

Although commonly referred to as Trident’s replacement, the ‘Dreadnought’ programme is about the design, development and manufacture of four new Dreadnought-class ballistic missile submarines. These will replace the Vanguard-class submarines and maintain the UK’s continuous at sea deterrence posture. The first submarine will enter service in the early 2030s.

A ‘Common Missile Compartment’ for the submarines, which will house the Trident strategic weapons system, is being developed in conjunction with the United States. Replacement of the Trident II D5 missile itself is not part of the Dreadnought programme.

Replacement of the nuclear warhead

A decision on replacing the third element of the nuclear deterrent, the warhead, was deferred in the 2010 Strategic Defence and Security Review until 2019/20.

The Ministry of Defence (MOD) has been undertaking work on possible replacement options, including with the United States. In May 2019, the MOD confirmed that work was continuing on refining options and technical solutions to inform the Government’s decision.

When might a decision be made?

Arguments over the nuclear deterrent are likely to re-emerge post-election as a Government decision on replacing the UK’s nuclear warhead will need to be taken during this Parliament if the project is to be completed by the late 2030s. The MOD has estimated that, after an initial decision, it would take 17 years from an initial decision to bring a new warhead into service.

Whether a decision will be made as early as 2020 remains to be seen. March 2020 will mark 50 years since the Nuclear Non-Proliferation Treaty (NPT) came into force. The 2020 NPT Review Conference is widely expected to criticise the nuclear weapon states for their pursuit of nuclear modernisation at the expense of their Article VI disarmament obligations, and for their failure to sign up to the Treaty on the Prohibition of Nuclear Weapons.

Successive British Governments have argued that the NPT contains no prohibition on updating existing weapons systems and gives no explicit timeframe for nuclear disarmament. They have also highlighted the UK’s disarmament achievements since the end of the Cold War, which will reach a 65% reduction in the UK’s stockpile by the mid-2020s.

A decision on replacing the nuclear warhead within the context of forthcoming NPT milestones could be controversial and is more likely to be addressed later on in this Parliament.

Article VI of the NPT

“Each of the Parties to the Treaty undertakes to pursue negotiations in good faith on effective measures relating to cessation of the nuclear arms race at an early date and to nuclear disarmament, and on a treaty on general and complete disarmament under strict and effective international control.”

How much will it cost?

The cost of the Dreadnought submarine programme is estimated at £31 billion, including defence inflation over the life of the project. A £10 billion contingency has also been set aside.

At potentially £41 billion, the programme will be the most expensive in the MOD’s equipment plan.

Once the new nuclear deterrent comes into service, the annual in-service costs are expected to remain at approximately 6% of the defence budget (£2.3 billion per year).

These in-service costs are often contrasted with the benefits bill or NHS spending.

To date, the project remains within its cost estimate.

In line with convention, the programme will be paid for by the MOD. The National Audit Office has raised concerns about its impact on the affordability of the MOD’s equipment plan.

The Campaign for Nuclear Disarmament has suggested that the true cost of replacing the nuclear deterrent will be in excess of £200 billion, once other costs, such as infrastructure, maintenance and decommissioning are considered. Advocates for the programme argue that the price is small when compared with the strategic risks involved in renouncing the nuclear deterrent.

How do different parties view the replacement?

Parliament has its opponents to the nuclear deterrent, including the SNP, the Green Party and senior figures within the Labour Party, including Jeremy Corbyn.

Although support for the nuclear deterrent is official Labour Party policy and stated in its election manifesto, Jeremy Corbyn has previously said that he would never authorise its use. The SNP continue to campaign for the removal of nuclear weapons from Scotland.

In comparison, the Conservative Party has consistently shown support for the nuclear deterrent, while the Liberal Democrats have committed to maintain a “minimal” credible deterrent.

Further reading

Insights for the new Parliament

This article is part of our series of Insights for the new Parliament. This series covers a range of topics that will take centre stage in UK and international politics in the new Parliament.

Image: 45159434 / Ministry of Defence, Open Government Licence