The Nuclear Outlook for the Next Government

Main Image Credit HMS Vengeance returning to HMNB Clyde, after completing Operational Sea Training. Courtesy of POA Tam McDonald/Ministry of Defence

Britain’s newly elected Parliament, due to be opened by the Queen next week, promises to be a busy one for nuclear issues. As the new government takes shape, the Proliferation and Nuclear Policy team at RUSI outlines some of the key decisions that it will have to make.

Forever Delayed: A New Nuclear Warhead?

Successive governments have declined to make a decision on a new warhead for the UK’s nuclear deterrent.

The Labour government argued in 2006 that, since the current warhead was likely to last into the 2020s, a decision would be required in the subsequent parliament. In 2010, the Conservative–Liberal Democrat coalition’s Strategic Defence and Security Review (SDSR) announced that a new warhead was now not needed ‘until at least the late 2030s’, and that a decision on replacement could therefore be deferred.

More recently, and after the 2015 General Election, the 2015 SDSR broadly confirmed the previous timetable and indicated that a replacement decision ‘may be required in this parliament or early in the next’.

In practice, the UK will be reluctant to make decisions before it knows what US warhead replacement programmes look like, but its hand may be forced if Washington decides to delay.

Either way, the nuclear deterrent programme will be under significant cost pressure over the lifetime of the incoming parliament, assuming, of course, that no snap elections are called.

The National Audit Office hanoted that the already substantial affordability risks of the defence programme have been exacerbated by falls in the value of the pound associated with fears over Brexit.

It seems unlikely that deterrent programmes will be entirely protected from budgetary depredation, so the government will have to take a view – and quickly – as to where its priorities within that programme lie.

Everything Must Go: The UK and Disarmament Diplomacy

The UK has traditionally sought to be demonstrably compliant with its disarmament obligations under the Nuclear Non-Proliferation Treaty (NPT) – through unilateral reductions in warhead numbers, reduction in deployed systems and leadership in disarmament forums.

However, following an acrimonious breakdown in consensus at the 2015 NPT Review Conference, the NPT framework is delicate.

With a majority of non-nuclear weapon states currently pursuing negotiations on a treaty banning such weapons, Britain’s incoming government will need to tread carefully if it wants to avoid a rough ride in its attempts to support existing norms during the current review cycle – especially if a decision is made to develop a new nuclear warhead.

In terms of a disarmament offer, the UK has very few steps it can take unilaterally if it does not want to abandon continuous at-sea deterrence; it is hard to see how a further cut in warhead, missile or platform numbers could be reconciled with a posture of minimum credible deterrence; and changes in declaratory policy are simply less compelling than changes in capability.

Arms control and verification research projects are, therefore, likely to be at the foreground of any UK offer. But disgruntled states will want to see practical action rather than political showpieces, and the UK and its partners will have to work hard to convince them that they remain eager to engage in the former, rather than the latter, sort of activity.

Know Your Enemy: Countering Global Proliferation

Turning to international challenges, Iran and North Korea will continue to dominate the agenda. In the case of North Korea though, the UK has only limited levers to pull.

It can continue to play an important supportive role as the closest US ally with a diplomatic presence in Pyongyang and a permanent presence in the UN Security Council. The UK government can work with others to counter North Korean proliferation worldwide and mitigate the crisis, but is unlikely to take the lead on such policy.

The same could not be said in the case of the Iran nuclear agreement. Washington’s commitment to the deal remains unclear, and a substantial portion of the US legislature is far from convinced of its merits.

New sanctions measures pursued in the US Congress (which Iranian news outlets have alleged are breaching the terms of the nuclear agreement), will need to be balanced by assurances from the UK and its EU partners.

The UK government will therefore need to decide how much capital it wants to spend on protecting the deal, in Washington and elsewhere. This may require more than diplomatic capital, for our research reveals that despite European sanctions being lifted, EU financial institutions remain deeply cautious of exposure to US sanctions. This means, in turn, that entities in other sectors cannot easily re-enter Iran.

London’s position as a home for global financial institutions means that the new British government must determine whether it wants to remedy this situation in order to continue to persuade Tehran of the enduring benefits of the agreement and, if so, what new tools might be required, beyond those it has already deployed.

National Treasures: The Civil Nuclear Sector and Euratom

The nuclear issues facing the new government stretch beyond deterrence and proliferation: following the Brexit vote last summer, the government also announced its intention to leave Euratom.

As well as provision of what is, effectively, a single market for nuclear energy in the EU, Euratom provides legal, regulatory and safeguarding functions. It is legally separate from the EU, but is governed by its institutions such as the European Court of Justice.

If the government does not change course, it must begin to replace the various components of Euratom, including those that will provide a key regulatory framework for the construction of the new Hinkley Point C nuclear power station and other proposed new builds at the Sizewell and Wylfa Newydd sites.


With a minority government and the broader challenge of Brexit negotiations, it is possible that many of these issues could slide down the ladder of priorities in the immediate term. However, this should not be a reason for inaction; rather, the government must decide now how it will continue to address these nuclear issues. None of these challenges can be resolved quickly and will require sustained work by this government and those to come. 


Malcolm Chalmers

Deputy Director-General

Proliferation and Nuclear Policy

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Tom Plant

Director, Proliferation and Nuclear Policy

Proliferation and Nuclear Policy

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Emil Dall

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Cristina Varriale

Research Fellow

Proliferation and Nuclear Policy

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