It’s a scenario most of us would rather not think about, but here is what would happen in the event of the United Kingdom deploying their nuclear arsenal.

In the not so distant past, the prospect of nuclear annihilation seemed like a bygone relic of the Cold War, but not anymore.

In fact, being vaporised in a fiery mushroom cloud appears to be back in fashion, with US President Donald Trump calling nuclear war the ‘greatest threat to humanity’ in a recent interview.

“We spend a lot of money of nuclear weapons – the level of destruction is beyond anything you can imagine,” he told Fox News of America’s 5,044 warheads.

“It’s just bad that you have to spend all this money on something that if it’s used, it’s probably the end of the world.”

Donald Trump has branded the prospect of nuclear war the ‘greatest threat to humanity’ (Andrew Harnik/Getty Images)

So let us be pessimists for a moment and imagine the worst case scenario, what would happen if the UK ever found itself in a situation where its nuclear weapons were being deployed?

When and how would the UK deploy its nuclear weapons?

As of 2024, public records state that the UK has around 225 warheads, of which 120 are operationally available for deployment as part of its Trident programme, and ranks fifth out of nine in terms of nuclear capability.

The US ranks second, behind Russia who have around 5,580 warheads.

Only the Prime Minister can authorise the use of UK nuclear weapons

Although the UK is a member of NATO, which notably includes the Article 5 clause – ‘if a NATO member is attacked, all other members will consider it an attack on themselves’ – the alliance cannot call for nuclear weapons to be used in a collective response. This responsibility falls on the UK Prime Minister – currently Keir Starmer – to authorise the use of Trident.

Authorisation of the UK’s nuclear weapons comes from the sitting Prime Minister, currently Keir Starmer (Dan Kitwood/Getty Images)

Under what circumstance would the UK use its nuclear weapons?

According to the Government website, the primary function of the UK’s nuclear weapons is as a deterrent.

“We would consider using our nuclear weapons only in extreme circumstances of self-defence, including the defence of our NATO allies,” UK guidelines state.

“The UK maintains only the minimum amount of destructive power needed to guarantee our deterrent remains credible and effective against the full range of state nuclear threats,” the website added, stating that key details of our nuclear deterrent are kept ‘deliberately ambiguous’ to maximise its effectiveness.

Trident: never used or ‘always in use’?

Thankfully the UK has never been in a position in which its needed to use nuclear weapons, however the defence ministry states this doesn’t mean the weapons aren’t technically ‘in use’.

In fact, the position of the UK government is that our nuclear weapons are always in use as they ‘protect us every hour of every day’.

“By providing a credible and effective response option to extreme aggression, our nuclear deterrent reduces the likelihood of such an attack taking place,” the Ministry of Defence adds.

What is the ultimate goal of the UK’s nuclear weapons programme?

If countries having nuclear weapons in order to prevent other nations’ use of said nuclear weapons sounds like a catch-22, that’s because it is.

With the uneasy prospect of mutually assured destruction holding, for now.

However this doesn’t mean the UK isn’t hopeful for a future without the need for nukes, with the nation a signatory of the 1968 Treaty on the Non-Proliferation of Nuclear Weapons (NPT). The ultimate goal of the NPT is to prevent the spread of nuclear weapons, promote peaceful uses of nuclear energy and ultimately achieve global nuclear disarmament.

US President Donald Trump has issued a chilling warning about what he considers to be the ‘greatest threat to humanity’.

The businessman said in an interview with Fox News on Sunday (9 March) that we shouldn’t be prioritising climate change as ‘the biggest existential threat’.

He told the broadcaster that ‘the level of destruction’ of nuclear weapons ‘is beyond anything you can imagine’.

Trump, 78, who is in charge of America’s 5,044 warheads, which is only second to Russia’s 5,500, said: “We spend a lot of money of nuclear weapons – the level of destruction is beyond anything you can imagine.

“It’s just bad that you have to spend all this money on something that if it’s used, it’s probably the end of the world.”

The Republican insisted that he disagreed with former President Joe Biden on his alleged prioritisation of global warming being a bigger concern.

Donald Trump has issued a chilling warning about the reality of nuclear war (OLIVER CONTRERAS/AFP via Getty Images)

“The greatest is sitting on shelves in various countries called ‘nuclear weapons’ that are big monsters that can blow your heads off for miles and miles and miles,” he added.

Trump also said that he sent a letter to Iran’s Supreme Leader Ali Khamenei, with the hopes of negotiating a new deal with Tehran to restrain its advancing nuclear programme.

He wants to replace their plan with the one he withdrew America from during his first term in office.

“I’ve written them a letter saying, ‘I hope you’re going to negotiate because if we have to go in militarily, it’s going to be a terrible thing,’” Trump said.

“I would rather negotiate a deal. I’m not sure that everybody agrees with me, but we can make a deal that would be just as good as if you won militarily.

Trump says we need to prioritise nuclear war as the biggest threat to humanity (Getty Stock Images)

“But the time is happening now. The time is coming up. Something’s going to happen one way or the other.

“I hope you’re going to negotiate because it’s going to be a lot better for Iran and I think they want to get that letter.

“The other alternative is we have to do something because you can’t let them have a nuclear weapon.”

This comes after Trump said last month that he wants to talk to China and Russia about de-escalating their nuclear weapons programme.

“There’s no reason for us to be building brand new nuclear weapons. We already have so many,” he explained.

“You could destroy the world 50 times over, 100 times over. And here we are building new nuclear weapons, and they’re building nuclear weapons.

“We’re all spending a lot of money that we could be spending on other things that are actually, hopefully, much more productive.”

Footage previously shared by the Ministry of Defence reveals a brief look at the UK’s nuclear deterrent, following Donald Trump’s chilling admission about the ‘greatest threat to humanity’.

Since taking office earlier this year, US President Donald Trump has made sure his concerns about nuclear weapons are clear.

At the end of last month, he accused Ukrainian leader Volodymyr Zelenskyy of ‘gambling with WWIII’ during discussions about Russia’s invasion of the Eastern European country.

More recently, the 78-year-old claimed that nuclear war was a bigger threat to humanity than global warming, telling Fox News: “We spend a lot of money of nuclear weapons – the level of destruction is beyond anything you can imagine.

Fingers crossed this isn’t the view from your window anytime soon (Getty Stock Image)

“It’s just bad that you have to spend all this money on something that if it’s used, it’s probably the end of the world.”

He added: “The greatest [threat] is sitting on shelves in various countries called ‘nuclear weapons’.”

Although climate change does remain a threat to humanity – whether Trump likes it or not – he’s not wrong on the nuclear war front, with countless doomsday simulations showing the catastrophic damage which just one missile could cause.

What does the UK’s nuclear weapons system look like?

The UK is one of nine countries which possess nuclear weapons – the others being the US, India, Russia, Pakistan, Israel, France, North Korea and China – through its Trident system.

Following the decision to decommission other weapons systems in 1998, Trident remains the only UK nuclear weapons system in active service.

One of the UK’s nuclear defence systems (Jeff J Mitchell/Getty Images)

Beyond the fact that Trident consists of four operational Vanguard submarines armed with nuclear missiles, with at least one always on patrolling the seas covertly, there isn’t that much else to know.

This isn’t a surprise, given the fact that key details of our nuclear systems are kept ‘deliberately ambiguous’ in order to assure its ‘effectiveness’ as a deterrent.

However, the Ministry of Defence did previously reveal a glimpse of one of the country’s nuclear submarines in a video back in 2021, alongside an explanation of what the system is and how it works to protect the UK and its allies.

Watch the clip below:

The continued existence of a nuclear weapons system in the UK has long been a divisive one, with numerous campaigners over the years calling for Trident to be decommissioned, most notably the Campaign for Nuclear Disarmament (CND), which sprung up in the late 50s.

However, both the UK government and the Ministry of Defence have voiced their strong belief in keeping the weapons as a deterrent, with the latter stating: “By providing a credible and effective response option to extreme aggression, our nuclear deterrent reduces the likelihood of such an attack taking place.”

President Donald Trump has told Russia and Ukraine to ‘get to the table right now’ after revealing he’s considering implementing banking sanctions and tariffs on Russia.

Taking to his Truth Social platform, Trump explained Russia and Ukraine must come to a settlement agreement ‘before it is too late’.

“Based on the fact that Russia is absolutely ‘pounding’ Ukraine on the battlefield right now, I am strongly considering large scale Banking Sanctions, Sanctions, and Tariffs on Russia until a Cease Fire and FINAL SETTLEMENT AGREEMENT ON PEACE IS REACHED,” he wrote.

“To Russia and Ukraine, get to the table right now, before it is too late. Thank you!!!”

Trump’s comments come after Ukraine suffered an overnight attack from Russia in multiple locations and using a variety of weapons.

The BBC reports that at least 18 people, including four children, have been injured.

While it’s not clear what sanctions Trump could impose, such measures are usually taken to prevent a country from breaking international law.

Since the invasion of Ukraine three years ago, 21,000 sanctions have been imposed on Russia from various countries across the globe, including sanctions related to the country’s oil industry.

Trump says he’s considering implementing sanctions (Carl Court – Pool/Getty Images)

Just last week, Trump sat with Ukrainian President Volodymyr Zelenskyy where the world leaders discussed a minerals deal and how Russia and Ukraine could reach peace.

After a high profile fall out, in which Trump said Zelenskyy could return when he ‘is ready for peace’, Trump paused military aid to Ukraine.

A White House official anonymously revealed to Sky News: “President [Trump] has been clear that he is focused on peace.

“We need our partners to be committed to that goal as well. We are pausing and reviewing our aid to ensure that is contributing to a solution.”

There is currently no set length in place, while Ukraine has yet to respond to the move, as the pause will go into effect immediately.

Trump has urged Russia and Ukraine to make an agreement (VYACHESLAV PROKOFYEV/POOL/AFP via Getty Images)

The UK government has responded to the latest development, with a spokesperson telling Sky News that ministers are ‘absolutely committed’ to achieving piece in Ukraine.

“We remain absolutely committed to securing a lasting peace in Ukraine and are engaging with key allies in support of this effort,” a UK government spokesperson has said.

“It is the right thing to do, and is in our interest to do so.”