PARLIAMENTARY DEBATE
UK Nuclear Deterrent - 2 June 2025 (Commons/Commons Chamber)

(Urgent Question): To ask the Secretary of State for Defence if he will make a statement on the future of the UK’s nuclear deterrent.

I am grateful to my hon. Friend the Chair of the Defence Committee for this chance to set out the Government’s total commitment to the UK’s nuclear deterrent, which has been the bedrock of our national security for nearly 70 years. My right hon. Friend the Defence Secretary will shortly outline the details of the strategic defence review to the House, and that review will be underpinned by our nuclear deterrent, which is part of our blueprint for a new hybrid Navy, in which next-generation Dreadnought nuclear-armed submarines, and up to 12 SSN-AUKUS conventionally armed nuclear-powered submarines, will serve alongside best-in-class warships, support ships and new cutting-edge autonomous vessels, building on the £15 billion investment set out for the UK’s sovereign nuclear warhead programme in this Parliament. This is not only a manifesto promise delivered; it is our most important military capability secured for generations to come. This investment will also deliver a defence dividend of highly skilled, well-paid jobs across the country. Our nuclear warhead programme alone will create and sustain over 9,000 jobs, along with thousands more in supply chains.

To ensure that the demands of our nuclear programme can be met, we are working closely with industry partners, and are aiming to double defence and civil nuclear apprenticeship and graduate intakes. That will mean 30,000 apprentices over the next 10 years; they will be part of this historic renewal of our nuclear deterrent and our communities across the country.

The first duty of every Government is to keep their people safe. In a more dangerous world, peace and security are best achieved through deterrence and preparedness. As the son of a Royal Navy submariner, I thank our outstanding submariners who patrol 24/7 to keep us and our allies safe. We know that threats are increasing, and we must act decisively to face down Russian aggression in particular. Our nuclear deterrent is the ultimate guarantor of our security. The Defence Secretary will momentarily make a statement giving further details, but our proposals are possible only because of the Government’s historic decision to increase defence spending to 2.5% of our GDP by 2027—the largest sustained increase in defence spending since the end of the cold war. The Government have the will, the plan and the means to secure the nuclear deterrent for generations to come. We are making Britain secure at home and strong abroad.

I thank the Minister for his response, and your good self, Mr Speaker, for kindly granting the urgent question.

Following the report in The Sunday Times that the Ministry of Defence is looking to purchase American fighter jets that are capable of deploying tactical nuclear weapons, it is essential that the House gets clarity on the Government’s nuclear deterrent policy—an issue of critical national importance. How have the media got hold of such sensitive information on future nuclear deterrent plans, and what steps are the Government taking to investigate the leak?

If the Government are pursuing an air-launched tactical nuclear capability, that is a huge deal. It would represent a significant shift in the UK’s nuclear posture. Indeed, it would be the UK’s most significant defence expansion since the cold war. This raises serious concerns about our sovereignty when it comes to nuclear weapons, about strategic coherence with our current doctrine, and about the principle of continuous at-sea deterrence.

Despite the defence nuclear enterprise accounting for around 20% of the defence budget, it remains largely outside meaningful parliamentary scrutiny, including by our Defence Committee. This must change, so will my hon. Friend the Minister explain how Parliament will be enabled to scrutinise changes to the UK’s nuclear programmes? Have discussions taken place with the US, and what role would it play in this capability? Will the Minister confirm that the UK will retain full operational control over any nuclear weapons? Given that tactical nuclear weapons lower the threshold for nuclear weapon use, what assessment has been made of the risks of escalation? Will the Minister confirm that only the Prime Minister would have authority to use them, and only in extreme self-defence? Finally, has there been consultation with NATO allies on this potential shift? Decisions of this magnitude must be transparent. The future of our nuclear deterrent must be based on clarity, credibility and, above all, British control.

I do not want to eat the Secretary of State’s sandwiches, and I am acutely aware that the statement that he is about to make—

Don’t worry: The Sunday Times did it for us.

The Secretary of State will shortly lay out more details of the strategic defence review, but I am happy to answer a few of the questions from my hon. Friend the Chair of the Select Committee.

Parliament has the opportunity to scrutinise the outcomes of Lord Robertson’s strategic defence review via the House of Commons Defence Committee. I know that my hon. Friend will have the reviewers in front of his Committee shortly and will be able to ask them difficult questions. I am aware that there are proposals for how we scrutinise more sensitive and classified issues, and conversations between the House and the Government on that continue.

We of course continue to have conversations with the United States—our most important security partner—and with our NATO allies, but my hon. Friend will understand that I will not be able to detail the precise nature of those conversations to the House at this stage. I reassure him that we retain full operational control of our independent continuous at-sea nuclear deterrent—the backbone of our national security.

As I mentioned, it is the first duty of any Government to keep our country safe. The nuclear deterrent is the ultimate guarantor of our national security and our safety. I can confirm that only the Prime Minister has the power to launch nuclear actions.

I call the shadow Secretary of State, James Cartlidge.

I am grateful to the Chair of the Defence Committee for securing this important urgent question. Following comments in the press last month from Sir Simon Case, former head of the civil service, that the UK should consider air-launched nuclear capabilities, I wrote in the Express on 25 May that our nuclear deterrent needed to be made even more resilient, including the continuous at-sea deterrent, but also

“potentially, by diversifying our methods for delivering nuclear strike.”

I believe that it would be right to diversify our methods of delivering nuclear strike, because we have to recognise the threat posed by Russia in particular, and it has the ability to operate nuclear weapons at tactical and theatre levels. To deter effectively, we must be able do the same.

We support in principle moves to widen our nuclear capabilities, on the assumption that we do so working closely with our NATO allies. However, I gently suggest to the Government that they may need our support to carry that decision. I remind the Minister that eight of his Front-Bench colleagues voted against the renewal of our nuclear deterrent in 2016, including the Deputy Prime Minister, the Foreign Secretary, the Secretaries of State for Scotland and Wales, the Under-Secretary of State for Foreign, Commonwealth and Development Affairs, the hon. Member for Hornsey and Friern Barnet (Catherine West), and others. If the Minister was hoping that he could rely on the Liberal Democrats, let me say that not only did all but one of their MPs vote against Trident renewal in 2016, but as a condition of supporting the coalition Government, they shamefully demanded that we delayed the renewal of our nuclear submarines, leaving us to rely on older boats for far longer. That led to longer maintenance periods, and above all, directly contributed to the punishingly long tours of duty for our CASD naval crews.

Having had the privilege of serving as the Minister responsible for nuclear, and having chaired the Defence Nuclear Board, I understand why the Minister needs to choose his words carefully, but can he at least recognise that 204 days for a patrol is far too long, and that in addition to any plan to diversify the deterrent launch method, we must ensure that our strategic CASD enterprise has an effective and productive industrial base, delivering faster maintenance times? Finally, will he confirm what the estimated cost will be of delivering an air-launched option, and say by when he would expect that to be in service?

Let me again put on record my thanks to all members of our Royal Navy who go out on patrol, not just on our Vanguard-class submarines, but also on our Astute-class boats—and the previous T-class boats—that defend our deterrent while at sea. They guarantee our security by ensuring that there is a continuous at-sea nuclear deterrent every day, and have done so for over 70 years. Every Labour Member was elected on a manifesto commitment to a triple lock for our nuclear submarines: first, we will continue to support the continuous at-sea nuclear deterrent; secondly, we will build four Dreadnought-class nuclear submarines at Barrow, which we are committed to delivering; and thirdly, we will maintain and provide all the upgrades that are required for the continuous at-sea nuclear deterrent. That includes the renewal of our sovereign warhead, which the Defence Secretary will get to when he makes his statement on the strategic defence review later today. I am determined that we will guarantee our national security, and we will work across Government to do so.

I congratulate the Chair of the Defence Committee, my hon. Friend the Member for Slough (Mr Dhesi), on securing this important urgent question. He and the Minister referred to the need for full scrutiny by the House of such sensitive matters—something that has been pursued for over a year, under the previous Government and this one. Can the Minister provide any reassurance that that is finally progressing, after some delay when there was a change of Government?

Yes, I can. The Defence Secretary is open to those conversations, though there may still be a difference of opinion about the best way of scrutinising some of our most sensitive matters. I encourage my hon. Friend to continue her conversations with him.

I call the Liberal Democrat spokesperson.

We face a once-in-a-generation set of threats, including an imperialist Putin and a completely unreliable President Trump, who we cannot depend on to support our defence. Our nuclear deterrent remains the best and ultimate guarantor of the UK’s security. We must ensure that it meets the scale of those challenges, so it is right that the Government should look at ways to guarantee its effectiveness. Delivering the Dreadnought class on time is crucial to that, and I welcome the update that the Secretary of State provided before the recess on those timescales. Looking ahead, it is important that the House understands the purpose of any future addition to our nuclear deterrent, so will the Minister outline what discussions his Department has had on how further additions to the deterrent would positively bolster the UK’s security?

The United States remains the UK’s most important security partner: no two nations on earth are as integrated in their defence, intelligence and communications systems as the United States and the United Kingdom. That is a position that this Government intend to continue, because it is in our national interest to ensure we remain strongly connected with our partners in the United States. I am open to conversations about how we bolster our deterrence. Indeed, I believe the Defence Secretary may have more to add on that matter in his statement on the strategic defence review.

I support the increase in defence spending and I recognise the reasons behind it, but will the Minister indicate what impact it may have on the non-proliferation treaty?

This Government are proud to be increasing defence spending, with an additional £5 billion in our budget this year and an extra £13 billion by 2027, compared with the situation we inherited in cash terms at the last general election. It is right that we invest not only in our nuclear deterrence capabilities but in others. As a nation that abides by the rule of law, we will continue to do so in all matters, including those relating to nuclear proliferation.

The review has identified a gap in our capability to have tactical nuclear weapons in place, and that gap will have been noted elsewhere, among our adversaries. Will the Minister assure the House that the gap that has now been identified in British military power is being filled by other NATO allies until we are able to fill it ourselves?

This Government have a “NATO first” defence policy, so it is vital that we support and are enabled by our allies, especially those in NATO, and we will continue to do that. The strategic defence review may set out words in that regard. I do not want to get ahead of the Defence Secretary’s statement, so I will not give the full details here.

There is a consensus in this place about the importance of an independent nuclear deterrent to keep us safe, but there is far less understanding about the need and use of tactical nuclear weapons. Does the Minister agree that we need to foster a much better understanding of how the logic of deterrence works, and how it can be and is being undermined by countries like Russia? Only then can we explain why our nuclear deterrence needs to change to remain effective in protecting us.

A fundamental part of the conversations about the strategic defence review that Lord Robertson and the review team have been having since the Labour Government came to power is how we reinforce the concept of deterrence, and why the concept of deterrence is so important to our security. Our armed forces—some of the best in the world—have capabilities that should deter any aggression, and we will be further enhancing that through the measures set out in the strategic defence review, as the Defence Secretary will announce shortly. We want to deter aggression but, if necessary, we need to have the capabilities to defeat it, and that is what the strategic defence review, which will be announced shortly, will detail to the House.

As it was this issue that brought me into politics many decades ago, it is an absolute pleasure to hear the full-throated commitment of both the Government and the Liberal Democrats to the strategic nuclear deterrent. If the future of the American commitment to NATO were not in doubt, we would not need to think about tactical nuclear weapons ourselves, because that role has always been fulfilled by US tactical nuclear weapons allocated to the defence of NATO. Will the Minister assure the House that we have sufficient confidence in the willingness of the United States, despite the present Administration’s attitude to NATO, that the co-operation that we need for the future of our strategic nuclear deterrent is not in doubt?

I can indeed. The defence partnership we have with the United States, particularly on nuclear deterrence, is a strong one. We know that President Trump and the US Defence Secretary, Pete Hegseth, have reaffirmed their support for article 5 of the NATO treaty. As we build towards the NATO summit in The Hague, the UK will set out not only how we plan further to enhance our deterrence, but how we plan to ensure that collectively, across the NATO alliance, we are more lethal and more able to deter. The reason why that additional deterrence is necessary is the increased threats that we face as a nation, both conventional and cyber-threats, and increased nuclear threats.

The UK is one of five nuclear countries that are members of the non-proliferation treaty. Will my hon. Friend tell the House what steps his Government are taking to reduce the number of nuclear deterrents that our country carries, which is one of our obligations under the treaty?

As part of our commitment to non-proliferation, we continue to abide by all the measures of the treaties we have signed. Our renewal of our nuclear deterrent is necessary in a more dangerous world. As the ultimate guarantor of our security, it will be central to this Government’s defence plans in the future.

In pursuit of deterrence, will the Minister recommit to first use when either the strategic or tactical situation demands it?

If I read out our nuclear playbook at the Dispatch Box, the right hon. Gentleman would be one of the first people to raise concerns, so I decline that polite invitation to detail our nuclear strategy. That ambiguity is absolutely certain, but we do not have a first-strike policy, as he will know. As the only European NATO member to dedicate our nuclear deterrent in the defence of all NATO member states, we maintain that capacity not only in support of the United Kingdom. That is an important part of our collective deterrence.

Far from the claims by successive British Governments that Britain has an independent nuclear deterrent, is the reality not that it is entirely dependent on the United States both technically and politically? Instead of spending billions more on nuclear weapons while public services face real budget constraints, should we not honour our commitments under the nuclear non-proliferation treaty by working towards the global elimination of nuclear weapons?

Every Member on the Government Benches stood on a manifesto in support of the renewal of our nuclear deterrent and in support of a continued at-sea nuclear deterrent, building four Dreadnought-class submarines and providing the upgrades necessary to ensure the effectiveness of that system. That is a manifesto commitment that we can all be proud of, and it is one that this Government will stick to.

As the Minister has mentioned it, as has my predecessor as Chair of the Public Accounts Committee, the hon. Member for Hackney South and Shoreditch (Dame Meg Hillier), it is now over a year since the Public Accounts Committee produced a report on how sensitive scrutiny could be carried out in this House. This is really important, and it feels as though we are being given the run-around. Will the Minister commit to setting a date when the Government will give a decision on the matter?

As I replied to my hon. Friend the Member for Hackney South and Shoreditch (Dame Meg Hillier), conversations continue between Members of this House and the Defence Secretary. He is open to further conversations to try to find a way forward, and I am certain that he would welcome a conversation with the hon. Gentleman.

The Minister is right to highlight the nuclear deterrent as the cornerstone of our defence capability, but it is also a national effort. Will he join me in commending the unsung scientists and engineers at the Atomic Weapons Establishment for their world-leading and highly confidential work that ensures the ongoing independence of the UK’s nuclear deterrent?

I am very happy to do so. It is not just the scientists and engineers at the AWE who support our nuclear deterrent, but the engineers and apprentices in Devonport in my constituency who refit our nuclear submarines. The entire supply chain, from Rolls-Royce to BAE Systems, Babcock and countless other companies and organisations involved in this national endeavour, helps to keep our country safe. I commend all of them for their work and their contribution to our national security.

When we discuss the nuclear deterrent, we sometimes forget that this is the ultimate weapon of mass destruction, which, if it was ever deployed, would quite literally end civilisation as we know it. The Minister might not agree, but does he accept that opposition to nuclear weapons is a legitimate, moral position of conscience held by most people in most nations in the world? Will he and his Government colleagues stop trying to demean and insult those who simply and legitimately want nothing to do with these evil weapons and want them gone from their country and their community?

I recognise that there is a range of views on nuclear weapons. I also recognise that there are thousands and thousands of people in Scotland whose jobs are dependent on supporting our nuclear fleet, who do superb work at the bases on the Clyde and support not just the submarines, but our entire nuclear supply chain, through small and medium-sized enterprises and larger companies in factories, engineering workshops and other businesses across Scotland. I am certain that, although the hon. Gentleman and I might disagree on nuclear weapons, he was not speaking for those people when he made his point.

Earlier this year, along with a cross-party delegation of MPs on the armed forces parliamentary scheme, I visited Faslane. That was a very important visit for me, because the nuclear reactors on the V-boats are made in my constituency, but it was particularly concerning to hear about deployments that are now lasting over 200 days. That is totally unacceptable, so can the Minister tell us what steps he is taking to reduce the length of those deployments while maintaining our continuous at-sea nuclear deterrent?

As a Government, we are seeking to renew the contract between the nation and those who serve. In particular, for those submariners who are involved with our nuclear patrols, reducing the length of those patrols is a key part of what we have to do. One aspect that I can tell my hon. Friend about in this House is the investment going into our nuclear submarine refits. Ensuring that we can refit the submarines in time, on schedule and on budget is essential to rotating between the four boats. Previous Governments delayed renewing our nuclear boats; we are taking the decision to support the Dreadnought renewal, which will provide the cutting-edge capabilities necessary for our nuclear deterrent to continue in the future. I commend all those involved in our nuclear enterprise, from engineers to the submariners who serve on our submarines, for keeping our country safe.

Does the Minister agree that any party that aspires to government in this country should be wholeheartedly and unambiguously committed to our independent nuclear deterrent? I am afraid that that was not always the case when we had a coalition under the Conservatives because of our coalition partners, but I am very pleased that they have repented now. Is it not absolutely extraordinary that a party that now presents itself as some kind of alternative Government cannot even send a single Member of Parliament to sit in this House while we are debating this existential issue for the security of our country?

I agree with the hon. Gentleman that any party aspiring to government must not just understand how dangerous our world is, how the threats are increasing and how our nuclear deterrent is the backbone of our national security, but must also be part of those conversations. I note that Members from the party he refers to are absent from today’s debate.

We all want to live in a world in which a nuclear deterrent is not needed, but sadly we all recognise that we do not live in that world, and we are further from it than we were a decade ago. Does the Minister agree that whether we are discussing the UK’s nuclear capacity or any other capacity, we must have a NATO-first defence policy and lead within the alliance? While I am here, can I also congratulate the Veterans Minister on his epic feat up Everest last week?

My hon. Friend’s question gives me an opportunity to thank the Veterans Minister and celebrate his work in completing Operation Mountain Goat, the speed climb of Everest. I commend him and all those who did so on their aspiration to raise £1 million for veterans’ charities—that is something I think we can get behind on a cross-party basis.

It is absolutely essential that we continue to support our national security. The more that we can do so on a cross-party basis, the more the power of our deterrence is something we can shout loudly and proudly about, especially when it relates to directing increased defence spending towards UK companies, creating jobs nationwide and using defence as the engine for growth that it truly is.

I am in favour of this new method of delivery, which gives us more options and probably makes it less likely in the long run that nuclear weapons will be used. However, cost is key, and with 20% of the defence budget already taken up by the defence nuclear enterprise, it is clear that our conventional capabilities are suffering. Can the Minister tell us whether the increased cost of these new warheads will come out of the Ministry of Defence’s budget, or out of a special Treasury reserve, as has sometimes been the case previously?

The increase in defence spending that we have secured, which the Prime Minister announced in February, provides us with the opportunity not to just renew our conventional capabilities, but look at how we can further support our nuclear deterrent and build our cyber-capabilities. Taken together, that is how we will build that collective responsibility. I do not want to give the hon. Gentleman an incorrect answer, so I will write to him about the point that he raised.

Well, it was a question of two halves. I agree with the hon. Lady on the first half, and I am grateful for the cross-party nature of what we can achieve here. It is a source of great pride to all Defence Ministers that our strong support for our nuclear deterrent and our national security was in the Labour manifesto, which enjoyed incredible support at the last general election. We are not only bringing forward a strategic defence review that will update our capabilities, but bringing forward our commitment to spending 2.5% of GDP to April 2027—three years before anyone thought that was possible. It is thanks to the brave decision by the Prime Minister that we can renew our capabilities and increase our deterrent capability as a country.

It was a Labour Government led by Harold Wilson in the 1960s that initiated the nuclear non-proliferation treaty, and it was during the cold war that the number of nuclear warheads was reduced by the five declared nuclear weapon states. This announcement by the Secretary of State, and today’s talk of increasing nuclear warheads, is in breach of the nuclear non-proliferation treaty and is at variance with the global nuclear ban concept of getting rid of nuclear weapons. How is the world made safer by the ability to destroy it more times over than exists at present? Where is the strategy for nuclear disarmament? Where is the strategy for peace?

I recognise that the right hon. Gentleman’s question comes from a heartfelt and personal belief in nuclear disarmament. On this side of the House, we support international disarmament obligations to the ultimate goal of a world without nuclear weapons, and the obligation to pursue negotiations in good faith on effective measures relating to nuclear disarmament. I gently say to him, however, and to all hon. Members, that we are facing increased nuclear threats as a nation not just from established nuclear powers, but from the risk of proliferation of nuclear technology, especially as that technology becomes more mobile, portable and miniaturised. It was precisely for that reason that that featured as part of the strategic defence review that the Defence Secretary will detail further shortly.

We are not due to hit 2.5% of GDP for two years, and 3% is by no means guaranteed. With the continuous at sea deterrent ringfenced, spending on conventional forces is well under 2% and in the bottom third of NATO countries. Introducing an air-launched nuclear weapon into our arsenal is a significant change to our doctrine and might fundamentally change the way that all our forces operate. We spend less on defence than other NATO nations with a nuclear deterrent, so when will we achieve parity regarding spending on conventional forces specifically?

I am normally reasonably impressed by the hon. Gentleman on defence matters, but let me say politely that we have £5 billion extra in the defence budget this financial year thanks to the decisions by the Prime Minister and the Chancellor. By 2027, we will have over £13 billion more in cash terms compared with the situation that his party left. When it comes to increasing defence spending, we are doing it three years earlier. It is worth reminding him that the last time this country spent 2.5% of GDP on defence was under the last Labour Government. It is something that his party never achieved for a single day when it was in power.

Most military operations require an element of surprise, and the Government certainly achieved that by delivering the news of the return of tactical nuclear weapons through the medium of The Sunday Times. That marmalade-dropping moment aside, what impact will the apparent purchase of F-35 Lightning fighters from America have on the global combat air programme that we are putting together with Italy and Japan—or should I wait for the “You read it here last” strategic defence review?

In the spirit of the day, I suggest that the hon. Gentleman waits for the Defence Secretary’s statement that is coming soon. I am very aware that when people go to a gig, they want the main act, not the warm up, so I look forward to him speaking in due course.