FOR most of us, until last week, ISIS was either the Oxford University student magazine or an Egyptian goddess.

Now it has exploded into our consciousness as the most violent and gruesome of jihadist movements.

As it massacred its way through parts of Iraq, the blame game in the West was already in full swing: was it our fault?

Sorry, I mean, was it Tony Blair’s fault? Oh, and George Bush’s too?

If we hadn’t invaded Iraq in 2003, would it now be a source of stability in what is already one of the world’s most unstable places? As a soldier who served in Iraq in 2003, it is a question that is often put to me. When Zhou Enlai (Chairman Mao’s deputy) was asked for his assessment of the consequences of the French Revolution on its 200th anniversary, he famously replied that it was far too soon to tell.

He may have been right, and the same uncertainty applies to what happened in Iraq. We can only speculate what upheavals might have occurred had Saddam remained in power until the pent-up frustrations of the “Arab Spring”

exploded a decade later. Western intervention and miscalculation goes back a long way.

We drew the arbitrary lines on the map in the first place, when we carved up the Ottoman Empire after the Great War – the centenary of the start of which we are even now commemorating.

We armed and backed different regimes in pursuit of our global strategic interests as it suited us, for oil, the Cold War, or high-minded, if misguided, principle.

Saddam’s regime, and indeed, that of Assad were products of this history. Making sense of region is plagued with layer upon layer of complexity.

We should be clear, however – ISIS (The Islamic State of Iraq and Syria), came from Syria and not from Iraq. Its speciality in Syria was making war on those of that regime’s opponents which it considered insufficiently pure to be worthy of the rebel cause.

Although the consequences of these events will have profound implications for us, we are mere witnesses – we are not the cause.

What we are witnessing is warfare at the heart of Islam.

Firstly, there is a war between the Shia and Sunni branches of the faith. This is currently being fought by proxy in Syria, with Iran, and its client Hezbollah, supporting Assad’s Alawites, against the Saudis who are backing the Sunni rebels. Another theatre of conflict is the terrorising of Shi’ites in Pakistan by the Pakistan Taliban.

The other war is essentially a war by Sunnis against other Sunnis and, by extension, everyone else. These are the Islamists, the jihadists, Salafists, Al Qaeda, ISIS or whatever other guise they go under. They believe in a “purer” expression of Islam, to which all Muslims (and ultimately everyone else as well) must, if necessary, be forced to conform with.

The same antagonists are principals in both conflicts: a Salafist will as soon blow up a mosque full of Shi’ites, as he would behead a fellow Sunni for listening to western music.

We have to play our part by ensuring British values are fostered in our schools, that our security services are equipped to deal with the threat posed by young British men returning from Syria radicalised by their experience and we need to consider when and where we might sensibly intervene militarily – however badly we perceive that it might have turned out in the past.