Could World War Three be started by an accident? An off-course missile hit a Polish village close to the Ukrainian border on Tuesday, sparking fears of global retaliation.

On an inconspicuous night in 1962, most Western authorities sincerely thought that the world was facing imminent destruction.

We were on the knife's edge of complete nuclear annihilation, at the height of the Cold War, when workers at a military base in Minnesota awoke to the worst case scenario: a nuclear alarm. Soviet pilots were hurtling across the ocean, nuclear bombs in tow.

Except, of course, they were not, or our lives today would look quite different. It was a false alarm. The culprit? A clumsy, blissfully-unaware brown bear who set off the alarm quite by accident.¹

On Tuesday, we got a taste for how they must have felt in 1962. After months of thinly-veiled nuclear threats by Russia's President Vladimir Putin, a Russian missile fell on a Polish village on the Ukrainian border, killing two people.

It is the first time that the territory of a Nato country has been struck during Russia's nine-month war on Ukraine. The fifth article in Nato's joint treaty states that an armed attack against one country in the group (to which Poland belongs) "shall be considered an attack against them all".

In other words, attacking a Nato power is almost a surefire way to trigger a third, and probably nuclear, World War.

Except that this, too, turned out to be a tragic accident. The missile is now thought to have been fired by the Ukrainian army in defence against Russia's relentless air strikes on the country's infrastructure.

We like to think of international relations as a shrewd game of chess, but it is more often a game of dominoes. One small coincidence can change the course of history.

Some name this the "Franz Ferdinand effect" after an Archduke of Austria whose death led to World War One. The Archduke's driver took a wrong turn on a random day in 1914 onto a street where a Serbian assassin happened to be walking by.

Unable to believe his luck, the assassin shot and killed both the Archduke and his wife, leading Austria-Hungary to declare war on Serbia, roping Russia, France and Germany into war.

Unhappy coincidences like this happen more often than you would think. In the 1970s, US authorities were paralysed with fear that president Richard Nixon, who was suffering from a bout of unstable mental health, would press the nuclear button unprovoked.

Meanwhile, authorities in Moscow were four minutes away from sending retaliatory nuclear bombs to the USA in 1995 after they mistook a Norwegian space expedition for nuclear missiles.

But some encourage us not to catastrophise. Nowadays, with the benefit of experience, we have structures in place to prevent absolute devastation.

Although Nato's treaty obliges members to protect an attacked ally, they will most often respond with economic sanctions, not with military force. The group also enforces careful group dialogue before action.

But this comes as little consolation to others, who cite an increasingly unstable global backdrop, cyberattacks and despotic regimes as factors which could make us "stumble into" a nuclear war.²

Yes: History throws up countless examples of accidents which almost caused nuclear wars. Eventually, we will stop getting lucky. We can control some of the variables, but at the end of the day the law of probability wins.

No: Nato proved with its careful examination of the facts in the Poland missile case that the time of accidental wars is over. Accidents will happen, but we are well-equipped to understand and deal with them.

Or...Perhaps not, but why should we take the risk? We need immediate better regulation of nuclear weapons, or better yet we need to find a way to get rid of them altogether.