Odious, twisted, hate-filled thugs; arrogant and inadequate creeps, intoxicated by the pathetic illusion of power that comes with guns; poisoned by a perversion of religion into a contempt for all norms of civilised behaviour.

They are fighting not for freedom but for a terrifying Islamic state in which they would have the whip hand — and yet there is no dodging or fudging the matter: these are among the Syrian rebels who are hoping now to benefit from the flow of Western arms.

How is it supposed to work? How are we meant to furnish machine guns and anti-tank weapons to one set of opposition forces, without them ending up in the hands of men like the al-Qaeda-affiliated thugs who executed a child for telling a joke? The answer is that we have no means of preventing such a disaster, any more than we can control what kind of “government” the rebels — if they were successful — would form in Damascus.

What is happening in Syria is one of the greatest human and cultural catastrophes of our age. For two years the mortar rounds have been pulverising the cradle of civilisation. When I think of the happy days I have spent roaming the souk of Aleppo or the Umayyad mosque of Damascus, I am filled with grief, and I hear such awful tales of destruction that I almost dread to go back. The dead are said to number 93,000 just in the past two years. But what else could we possibly have done?