Guidance

The UK’s nuclear deterrent: the facts

The UK’s independent nuclear deterrent has existed for over 60 years to deter the most extreme threats to our national security and way of life.

From:
Defence Nuclear Organisation and Ministry of Defence
Published
16 March 2021
Last updated
28 March 2024 — See all updates

The UK’s independent nuclear deterrent has existed for over 60 years to deter the most extreme threats to our national security and way of life, helping to guarantee our safety, and that of our NATO Allies.

People understandably have strong feelings about nuclear weapons, but there are a lot of misconceptions about the UK’s nuclear deterrent. Here you can find the answers to 10 of the most common questions, and for more information, visit the UK’s Nuclear Deterrent: what you need to know.

Common misconceptions

1. As a weapons system designed during the Cold War, isn’t the UK’s nuclear deterrent obsolete today?

The threat of nuclear conflict did not end with the Cold War. The truth is that the security situation has worsened in recent years, with some states significantly increasing and diversifying their nuclear capabilities and behaving more aggressively. The UK must have the ability to protect itself and our NATO Allies.

Our independent nuclear deterrent remains an important part of our national security strategy and it is wrong to say it is never used. The reality is that our deterrent protects us every hour of every day. By providing a credible and effective response option to extreme aggression, the deterrent reduces the likelihood of such an attack taking place.

2. Could the UK not show global leadership by abandoning its nuclear weapons and setting a good example to other nations?

A world where the UK’s potential adversaries have nuclear weapons but we do not, is not a world in which you and your family are safer.

The UK is committed to the collective long-term goal of a world without nuclear weapons, but the significant steps we have made to reduce our nuclear forces have not always been matched by others. Some countries are developing new nuclear weapons and we must take sure these can never be used to threaten us. The UK giving up our nuclear weapons would not result in others doing the same.

Unilaterally abandoning our nuclear deterrent now would undermine our security, as well as that of our NATO allies, and put us all at greater risk. The only route to ridding the world of nuclear weapons is through gradual multilateral disarmament that takes account of the security situation we face. We know progress may feel slow and frustrating at times, but the reality is that there are no short cuts.

3. Wouldn’t the money spent on the nuclear deterrent be better invested in other public services?

The cost of operating, maintaining, and renewing the nuclear deterrent is substantial, but short-term economic pressure does not justify taking long term risks with the security of the UK and your safety. The cost of the renewal programme is spread over many years, recognising the decades-long life of the programme. This is in an investment in the protection of generations to come. The ongoing cost of operating our nuclear deterrent is only a small part of the Government’s total annual defence budget.

As a NATO member, the UK is committed to spending at least 2% of GDP (Gross Domestic Product) on defence. Leaving aside the costs of decommissioning and the economic impact on the tens of thousands of jobs across the UK directly supported by the nuclear deterrent, this commitment means any money taken from the deterrent would still need to be spent on defence. It would not be available for other public services, and would impose the much higher cost of weakening our ability to protect ourselves against the most extreme acts of aggression that threaten our national security.

4. Keeping a nuclear armed submarine at sea at all times is too expensive, couldn’t we just launch one if the security required it?

Maintaining a dormant deterrent, meaning a nuclear armed submarine would only be deployed in the event of a crisis, would cost about the same as it does to maintain our Continuous at Sea Deterrent (CASD).

All the highly complex equipment would still need to be maintained, with skilled personnel trained and ready. It would also give far less protection, making us more vulnerable to a pre-emptive strike.

Having to move our deterrent from a dormant state to an active one if we believed an attack was imminent could be viewed as an aggressive action. This could result in tensions being escalated, or lead to an actual conflict, making the situation much worse.

5. Doesn’t our nuclear deterrent make us more of a target?

No. Potential adversaries know we have the capability to inflict costs on them that far outweigh any benefits they could hope to achieve by threatening our security. This reduces the likelihood of an extreme act of aggression against us ever taking place.

We must continue to ensure potential aggressors can never use their nuclear capabilities to threaten or attack us or our NATO allies, and this is best achieved by maintaining our independent continuous at sea nuclear deterrent.

Taking away this ultimate guarantee of our safety would place us and our NATO Allies at much greater risk.

6. Aren’t the UK’s nuclear weapons illegal under international law?

No. The UK’s nuclear deterrent is fully consistent with our international legal obligations, including under the Treaty on the Non-Proliferation of Nuclear Weapons (NPT).

The UK is committed to the long-term goal of a world without nuclear weapons and continues to lead on global disarmament initiatives, but we will keep our deterrent for as long as the global security situation makes it necessary.

The UK does not support and will not sign or ratify the Treaty on the Prohibition of Nuclear Weapons (TPNW), and so will not be bound by its provisions. The TPNW risks undermining existing non-proliferation and disarmament efforts , and will not enhance our security.

The TPNW tries to find quick fixes and does not offer credible solutions to the complex security environment we face. We do not consider it to be compatible with NATO membership, and support NATO’s clear stated opposition to it.

7. Isn’t there the risk of a major accident involving the UK’s nuclear weapons that could do real damage to people and the environment?

The safety of our submariners, their families and the general public is of highest priority, and the UK takes the security of its nuclear materials extremely seriously.

All aspects of the defence nuclear industry, including the storage and maintenance of our nuclear weapons, and managing waste, are subject to very strict licensing and regulatory requirements. The Defence Nuclear Safety Regulator is responsible for regulating nuclear safety across the Defence Nuclear Enterprise, and provides independent assurance of compliance. It works closely with statutory regulators like the Environment Agency and the Scottish Environmental Protection Agency to ensure exceptionally high standards.

The UK’s nuclear weapons are designed with built-in features that make them safe until they may need to be used, and we minimise our impact on the environment wherever possible. This includes recycling most of the hazardous materials we need to maintain the deterrent by retrieving them from old weapons.

These protections mean the risk of a serious accident happening is extremely low, but even so, we have regularly tested plans in place to counter and respond to all conceivable incidents, no matter how unlikely they may be.

8. Surely the UK doesn’t need a nuclear deterrent as we are already protected by the US equivalent?

It is vital for our national security and your safety that the UK continues to be an independent global actor, able to stand up for ourselves and protect our citizens against the most serious threats.

If we were to rely on the US we would be outsourcing our security to another country. That would limit our ability respond in a crisis and make the work of potential adversaries easier. When thinking about an attack on the UK, they would only have to calculate how far they thought they could push the US commitment to protect the UK before Washington acted on our behalf.

Our deterrent makes a key contribution to European and Euro-Atlantic security, and is a fundamental part of NATO’s strategy. For as long as nuclear weapons exist, NATO will remain a nuclear alliance.

9. How can the UK’s nuclear deterrent make us safer if it can’t protect us against terrorism or cyber warfare?

The nuclear deterrent exists to deter the most extreme threats to our national security and way of life, which cannot be deterred by other means. It is not intended to work as a deterrent against non-nuclear terrorism, cyber attacks, or street crime in your local area.

In the same way, tanks, soldiers and police on the beat do not deter other states from considering carrying out a strategic nuclear attack against us.

Different threats require different responses, and the UK maintains capabilities which can deter and meet each of these in the most appropriate way.

10. Can’t our adversaries hack our nuclear weapons?

No. No other state has the technical means to override launch instructions of the UK’s nuclear weapons.

The deterrent’s command and control system is fully independent, and we have full operational control over its use. Only the Prime Minister can authorise the use of our nuclear weapons, even if deployed as part of a NATO response.

The instruction to fire would be transmitted to the submarine using only UK codes and UK equipment. Our submarines can operate without the Global Positioning System (GPS), and contrary to what is often said our nuclear missiles do not use it at all.

Updates to this page

Published 16 March 2021
Last updated 28 March 2024 + show all updates

  1. Updated 'Related information'.

  2. First published.

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