Isil are also cunning and well organised, and very hard to defeat. In less than a year, they have turned much of Iraq into a shambles. They have caused about 7.6 million people to flee their homes – anyone of a different religion, anyone who refuses to bow, anyone who won’t pay the tithes, anyone who objects to their programme of slaughter and rape. I talk to a Shi’ite muezzin from a Mosul mosque, and as we sit on the floor of his tiny bivouac, he alternately weeps and rants as he describes the failings of the Iraqi army. They have done nothing to protect him. Iraq as a country is no good, he says – and as far as he is concerned, Mosul should be handed over to the Kurds.

The UK is pledged to help these Peshmerga, and we can certainly be proud of what is being accomplished. The RAF has launched dozens of sorties, dropping Paveway and Hellfire munitions on the Isil insurgents, often with success. I went up in the hills, about 30 miles from the front, to watch men and women from the British Army giving tuition in the basics of warfare. There on rolling green terrain – looking a bit like a shooting party in northern Spain – the weather-beaten Peshmerga were learning to advance in formation, to avoid ambush, to take out wounded comrades. There is no doubt that the Kurds are grateful for what we are doing, and especially for help with their 1.5 million refugees.

But it is important not to exaggerate our military contribution. We have given them 40 heavy machineguns and half a million rounds, and we have a total of 75 troops deployed, with very strict rules of engagement. We are not even teaching them such essentials as how to remove an improvised explosive device. I look at these Kurds and the scale of the challenge they face – Mosul is still occupied by Isil – and I cannot help wondering if we could do more. Those anti-tank weapons that worked so well the other night: they came from Germany. Couldn’t we send some more?

Of course I understand the anxieties of the UK Government: the strong and justifiable aversion to sending British ground troops to the frontline. Then there is the basic uncertainty about how any more weapons might ultimately be used, and against whom. It may be that the future for Iraq is a more federal structure, with even more autonomy for Kurdistan – but no one wants to see a violent break-up; no one wants a disintegration of relations between Baghdad and Erbil, the Kurdish capital.

All these political questions are important and delicate, but they strike me as fundamentally questions for another day. The immediate task is to help the Kurds defeat the forces of darkness and hate. It is hard to think of another conflict where righteousness coincides so overwhelmingly with the British interest. In a miserable region, Kurdistan is an oasis of democracy, tolerance, prosperity, openness and relative gender equality. Since John Major’s 1991 no-fly zones, the Kurds have been vehemently pro-West, and particularly pro-British. With the sixth-biggest notional oil reserves in the world, Kurdistan is a huge opportunity – and already has the most successful Jaguar Land Rover showroom in the Middle East.

Now is exactly the time, when things are tough, for us to step up our support: encouraging more trade, and more direct flights from London to Erbil, and above all to spread the news to British business that Kurdistan is really different, and in some ways better. And we should consider intensifying our military support. In a struggle against savagery that washes up on our shores, their cause is our cause.