The definition of nuclear weapons, and how many Russia has compared to the UK and Nato (2024)

Russia’s invasion of Ukraine was not even a week old when Vladimir Putin started making nuclear threats.

Last weekend he ordered forRussia’s nuclear deterrent forces to be put on high alert, blaming Nato aggression, despite Nato being a defensive alliance.

He has warned other countries against interfering in Ukraine, saying: “To anyone who would consider interfering from outside: If you do, you will face consequences greater than any you have faced in history. All the relevant decisions have been taken. I hope you hear me.”

The Russian leader later issued what many took to be a threat of nuclear war, adding: “Russia, even after the collapse of the USSR and the loss of a significant part of its nuclear potential, is today one of the most powerful nuclear powers.

“And moreover, it has certain advantages in a number of the latest types of weapons. In this regard, no one should have any doubt that a direct attack on Russia will lead to defeat and dire consequences for a potential aggressor.”

What are nuclear weapons?

Britannica describes a nuclear weapon as a “device designed to release energy in anexplosivemanner as a result ofnuclear fission,nuclear fusion, or a combination of the two processes”.

In simple terms, nuclear fission isthe splitting of a large atomic nucleus into smaller nuclei, which causes atoms to become violently unstable.

Nuclear fusion is when two light nuclei fuse to make one heavy nucleus, with the difference is mass causing energy to be released.

Weapons that use nuclear fission are commonly referred to as atomic bombs, while those that use nuclear fusion are called hydrogen bombs or thermonuclear bombs.

Nuclear weapons produce an enormous amount of explosive energy. The bomb dropped on Hiroshima during the Second World War only contained around 64kg of uranium, and yet created a blast the size of 15,000 tons of chemical explosive.

Nuclear explosions create an enormous shock wave, intense heat and release radiation. This radiation can spread far beyond the scene of the blast, and cause devastation for month after the explosion, killing people through burns,radiation sickness and other injuries. Exposure to radiation can also cause cancer and other long-term health problems.

The atomic bombs the United States dropped on Hiroshima and Nagasaki during the Second World War remain the only times nuclear weapons have been used in armed conflict.

They killed between 129,000 and 226,000 people, the vast majority civilians.

Which countries have nuclear weapons?

There are nine countries known to have nuclear weapons; the US, the UK, Russia, China, France, Pakistan, India, Israel and North Korea.

The Treaty on the Non-Proliferation of Nuclear Weapons, shortened to the Non-Proliferation Treaty (NPT), is an international agreement signed by 191 countries intended to stop the spread of nuclear weapons.

There are three main parts to the agreement: non-proliferation, disarmament, and the right to peacefully use nuclear energy.

The US, UK, Russia, China and France have all signed the agreement. Pakistan, India, Israel, and North Korea are not part of it.

North Korea initially signed the treaty, but withdrew from it in 2003.

After the dissolution of the Soviet Union in 1991, Ukraine held about one third of the union’s nuclear weaponry.

At the time it held the third biggest nuclear arsenal in the world, with an estimated 1,900 strategic warheads, 176 intercontinental ballistic missiles and 44 strategic bombers.

However, by 1996 it had returned all of its nuclear warheads to Russia in exchange for economic aid and security assurances.

How many nuclear weapons does Russia have?

Russia has the most nuclear weapons of any country, at 6,257.

Of these, 1,458 are active, meaning they are already deployed, 3,039 are available (can be deployed if needed) and 1,760 are retired (out of use and awaiting dismantlement).

The US follows with 5,550 nuclear weapons, of which 1,389 are active, 2,361 are available, and 1,800 are retired.

Of the remaining NPT countries, China has 350 active nuclear weapons, France has 290, and the UK has 225.

This means that Russia and Nato have very similarlt-sized nuclear arsenals.

Pakistan, India, and Israel have have 165, 156, and 90 available nuclear weapons respectively.

Where are the UK’s nuclear weapons?

The UK initiated its nuclear weapons programme, codenamed Tube Alloys, during the Second World War, and by 1952 it became the third country in the world to develop and test nuclear weapons, after the US and the Soviet Union.

Today, Trident is the only operational nuclear weapons system in British service.

Trident consists of four submarines, is operated by the Royal Navy and is based at HMNB Clyde in Scotland.

Each submarine is armed with up to sixteen Trident II missiles, which each carry warheads in up to eight multiple independently targetable re-entry vehicles (MIRVs). One submarine is always on patrol.

The Ministry of Defence says Trident’s role is to “deter the most extreme threats to our national security and way of life, which cannot be done by other means”.

Could there be a nuclear war?

Defence Secretary Ben Wallace said President Putin’s move to put Russia’s nuclear deterrent forces on high alert is “about distracting the world and the public from what he’s actually doing in Ukraine”.

He told Sky News: “It doesn’t link to anything specific in their readiness structures of their forces.

“We keep it under review, but of course Nato has a nuclear deterrent, the United Kingdom is Nato’s nuclear deterrent, and we keep our readiness very high.

“That’s why we have a continued at sea deterrent. But we shouldn’t really forget that this is a big attempt to distract away from his troubles in Ukraine by just deploying into the sort of media space these phrases.”

A senior White House official called President Putin’s move “yet another escalatory and totally unnecessary step”.

They said in a statement: “At every step of this conflict, Putin has manufactured threats to justify more aggressive actions.

“He was never under threat from Ukraine or from Nato, which is a defensive alliance that will not fight in Ukraine.

“The only reason his forces face a threat today is because they invaded a sovereign country, and one without nuclear weapons.”

Hans Kristensen, director of the Nuclear Information Project at the Federation of American Scientists, told Vox: “I’m more worried than I was a week ago.

“Putin has now taken yet another step that unnecessarily escalates the situation to what appears to be a direct nuclear threat.”

Matthew Bunn, professor at the Harvard Kennedy School and former adviser to Bill Clinton’s Office of Science and Technology Policy, added: “I think there is virtually no chance nuclear weapons are going to be used in the Ukraine situation.

“No one outside of Putin’s inner circle knows for sure why Putin has taken this action My guess – and it’s only that – is that it is intended as further signaling to deter anyone in the West from even thinking about intervening militarily to help Ukraine.”

Where everything could change is if Russia were to invade a Nato country.

Nato uses a system of collective security, whereby its independent member states agree to mutual defence in response to an attack by any external party.

This means were Russia to attack a Nato state such as Estonia, Latvia or Lithuania, it would then be at war with all 30 Nato members.

The US, UK and France all have nuclear weapons, meaning any war between Russia and Nato has the potential to be devastating.

However, President Putin will know how risky attacking Nato would be, as Nato’s combined forces are significantly larger than his own.