A full-scale nuclear war would likely devastate the planet for generations, with recent academic research suggesting such an event could kill five billion people.
With this in mind, will the next Prime Minister taking up office on 6 September, demonstrate that they have what it takes to make the right 'yes' or 'no' decision to command the series of orders that would launch a nuclear strike from the UK – what might be colloquially referred to as pushing the 'Red Button'?
There may be no actual button, more a procedure following a strict chain of command, but nuclear weapons expert Hamish de Bretton-Gordon OBE, a former British Army officer and former commanding officer of the UK's Joint Chemical, Biological, Radiological and Nuclear Regiment and NATO's Rapid Reaction CBRN Battalion, gives his view on what would be expected of the next leader of the United Kingdom.
Pressing the red button – to press or not to press?
The first task of government is to protect the nation, and the primary job of the prime minister is to take the decisions and actions which will protect the people.
In this area, the ultimate task of the premier is to press, or not, the red button to unleash the country's nuclear deterrent to save the nation.
This is not a yes/no act, and the decision is far from binary. A full-scale nuclear war, probably resultant from this, would likely devastate the planet for generations, and if a new report out of Rutgers University in the US is to be believed, could kill five billion people.
Hence, it is not too surprising the umbrage caused when the lead contender to be the next prime minister answers this most complex of questions, with the simplest exclamative noun – yes!
Understandably, Liz Truss is, at the moment, trying to get over the line with the 100,000 or so Conservative folk who vote, and who want to be sure their commander in chief has the firmest of hands to press the aforementioned button.
But these are true blue supporters of our nuclear weapons, and all forms of military action are needed to keep the latest Russian expansion to a minimum.
On 5 September, Liz Truss or Rishi Sunak will be given the codes for the red button and have the ability to launch Armageddon.
Then, it is really the 67 million other occupants of the United Kingdom who deserve the assurance that the yes or no answer does not just casually trip off the tongue, but has intellectual rigour, the best intelligence and the best advice behind it.
The UK's nuclear deterrent is based on the Trident missile system, which is located in four Royal Navy submarines, with one always at sea and ready to go.
The basis of ours, the US' and France's nuclear deterrent is Mutually Assured Destruction, with the amusingly ironic abbreviation, MAD, between the West and Russia.
MAD has kept the peace for more than 60 years, but nuclear proliferation in the last few years has brought new players onto the nuclear scene, making life more complex and the chance of miscalculation or misjudgement that much higher.
And, at a time when China is tripling its warheads, Iran is claiming to be nuclear-capable and North Korea trying hard to get there.
Not forgetting that Pakistan and India, which have been in a general state of conflict since independence, are also believed to have significant nuclear warheads.
Against this backdrop, hopefully, the new premier begins to understand that pressing the red button is far from straightforward.
Watch: Ukraine: Why risk attacking a nuclear plant?
Our new leader will immediately have a number of issues to ponder in this area, if the war in Ukraine or situations elsewhere, mean that the locks on the nuclear briefcase need to be oiled.
Although our nuclear deterrent is completely independent, the first challenge to the premier is whether to use it in such a manner. Can we really envisage using Trident independently without the US and, also possibly, France?
If we did, for argument's sake, against Russia, their nuclear weapons could wipe Britain off the planet, rather than just create massive destruction, as in a global nuclear conflict; which, I think, with the right preparation, enough people and infrastructure could survive to ensure the survival of the country in the longer term.
I personally cannot see an occasion where we might use our weapons independently.
Watch: HMS Anson joins the Royal Navy fleet.
Much of the hubris around nuclear weapons can best be described as strategic brinkmanship – President Putin, the master of this art, is threatening the UK directly with nuclear attack since the beginning of his invasion of Ukraine, presumably to keep us out of the direct fight.
He very publicly put his nuclear troops on high alert; ours are always on high alert.
He's turned Zaporizhzhia nuclear power station into a sort of improvised nuclear device and threatened to use 'smaller' nuclear bombs on the Ukrainian battlefields.
I would like to know if the new leader would press the red button if Putin blows up Zaporizhzhia.
We know much of the nuclear fallout would come our way. Would he/she use Trident if Putin uses battlefield nuclear weapons in Ukraine? Not quite a 'yes' or 'no' answer, but the nuclear conundrum begs more than the shortest of nouns in qualification.
I have no strong feelings on whether Truss or Sunak should lead us next. I'm not that bothered who is cutting or raising taxes, as I know inflation will come down once the war in Ukraine ends, and the sooner we can enable this the better.
The one who gets my vote is the one who demonstrates they can make the right 'yes' or 'no' decision on the red button – if they were not prepared to press the red button in the first place, they should not be in politics, let alone vying to be leader of our great nation.
Hamish de Bretton-Gordon OBE is a former soldier. He was commanding officer of the UK Chemical, Biological, Radiological and Nuclear (CBRN) Regiment and NATO's Rapid Reaction CBRN Battalion and is one of the world's leading experts on chemical and biological counter-terrorism and warfare. He is a fellow at Magdalene College, Cambridge.