George Grant was the Conservative Parliamentary Candidate for Bradford West at the 2015 election.

Stalin once said that if you kill one man they call it a tragedy; kill a million and they call it a statistic.

Nobody quite knows how many have died in Syria’s brutal, unrelenting civil war. Estimates range from some 200,000 up to nearly half a million.

For most of the outside world, the Syrian people have long since relinquished their humanity and taken on the form of a statistic, and one to be inadequately recorded at best.

Yet just occasionally events in Syria retain the capacity to shock. Tuesday’s chemical weapons attack on the frontline town of Khan Sheikhoun, in which almost 100 people are now believed to have died, has done just that.

Witnesses reported that, in the early hours of Tuesday morning, missiles filled with sarin nerve gas were fired from planes into the rebel-held town, suffocating civilians as they slept.

Hours after the attack, a hospital treating the injured was hit in a second strike. Images taken inside the clinic and in evacuation areas nearby appear to show rows of small, lifeless children, some with foam – a symptom of sarin gas – visible near their mouths.

How has it come to this – the deadliest attack involving chemical weapons in Syria since August 2013, when 1,300 were killed in the suburbs of Damascus?

The Syrian regime has, of course, denied all involvement. Their Russian sponsors have claimed the incident was the result of a Syrian airstrike targeting a “terrorist warehouse” containing chemical weapons destined for jihadis in Iraq, and that it was the fallout from this hit that caused the gas to be unwittingly released.

This latter claim has been dismissed by a prominent chemical weapons expert as fanciful: “if you blow up sarin, you destroy it”, Colonel Hamish de Bretton-Gordon, a British chemical weapons specialist, told the BBC, adding that: “The view that it’s an al-Qaeda or rebel stockpile of sarin that’s been blown up with an explosion is completely unsustainable and completely untrue”.

We know that rebel forces in Syria are not operating fighter jets in the conflict. We know also that Khan Sheikhoun is not in the hands of Islamic State, the target of coalition airstrikes in the country. This just leaves the Syrian Government and their Russian sponsors as possible culprits.

Russia has said its planes were not operating in the area and have rather let the cat out of the bag with their semi-defence of the Syrian regime, viz the claim that Syrian jets did indeed launch a strike in the vicinity, but only on the aforementioned “terrorist warehouse”.

What this war crime seems to confirm, therefore, is that Bashar Al-Assad’s government retains possession of chemical weapons, and that it remains prepared to use them.

Yet weren’t we given assurances back in June 2014 that the Syrian regime had disposed of the last of its chemical weapons, supervised by the Organisation for the Prohibition of Chemical Weapons (OPCW) in The Hague?

This process was the result of the much-vaunted ‘deal’ between the United States and Russia following the Damascus chemical weapons attack the previous August. But what stood behind this deal to guarantee its implementation? The answer is nothing but irresolution and weakness, and the results of that have now been visited upon the people of Khan Sheikhoun.

In August 2012, Barack Obama declared his ‘red line’ on the use of chemical weapons in Syria. “We have been very clear to the Assad regime, but also to other players on the ground, that a red line for us is we start seeing a whole bunch of chemical weapons moving around or being utilised”, Obama told the world. “That would change my calculus. That would change my equation.”

Yet when chemical weapons duly were deployed almost exactly a year later the result was not an enforcement of that red line, but prevarication, delay, and then nothing at all.

This failure to act, do not forget, was itself partly the result of British politics, when David Cameron’s motion to join US-led airstrikes was narrowly voted down in the House of Commons. Speaking immediately after the vote, the then Labour leader Ed Miliband claimed that in leading opposition to any military action he had stopped “a rush to war” and spoken “for the people of Britain”.

But a rush to war is precisely what this failure to enforce the chemical weapons red line did not prevent. The war was already on, and hundreds of thousands had already died as a result of it. On the contrary, this action, or rather lack of it, simply gave the Assad regime a very clear signal that deploying chemical weapons against his own people would reap no consequences.

Those who oppose military intervention in Syria rightly say that moving to depose Assad through armed force is futile if no plan exists for what comes afterwards. Indeed, if what comes after is the assumption of power by Islamic State then many will claim, not without cause, that no action is better than action for its own sake.

But that is not what is at stake here. The decision by Western powers over how to constructively engage to resolve this conflict is rightly so intractable because almost all the options are equally awful. But enforcement of the red line against chemical weapons in 2013 wouldn’t have been about choosing sides. It would have been about sending a very clear message that even in a war as terrible and seemingly unrestricted as Syria’s, some small lines of humanity still exist.

All weapons have the capacity to maim and kill, but in the past few decades the international community has been relentless in its effort to restrict and prevent the use of weapons that do so without discrimination. Close to the top of that list are chemical and biological weapons. 192 states are signatory to the Chemical Weapons Convention (CWC), including, since September 2013, Syria.

Yet as with so much else, these conventions derive their power not simply from the moral rectitude which underpins them, but from the capacity and will to seem them enforced. Indeed, without the latter, the former becomes nothing more than a warm glow to make us feel good.

And for those, such as the regime of Bashar Al-Assad, for whom moral rectitude has long ceased to be any consideration at all, enforcement is all that matters. When that enforcement was not forthcoming following the regime’s breach of the red line in 2013, nothing remained. Tuesday’s attack was surely proof of that fact, and a direct consequence of it. Do not expect it to be the last.