They are killing, raping, beheading and burying alive. They are offering people the choice of converting to Islam or facing instant execution. They have so terrified the population of northern Iraq – with its patchwork of ethnic groups and faiths – that the minorities have fled for their lives. As of today, there are still tens of thousands camped out on bare hillsides, their children dying of thirst, in scenes of biblical horror.

We are watching a catastrophe unfold, and the Prime Minister is absolutely right in his instinct – that Britain must act, and that Britain must help. I know how people feel these days about getting involved in overseas conflicts. There is a deep weariness and cynicism that has entered the bones of the nation – a sense that we were all bamboozled by Blair over Iraq, and that we won’t be fooled again.

People will look at the tragedy of the Yazidi and the Christians, and they will reasonably ask why we are choosing to try to help here, when we decided in the end there was nothing we could do for the Syrians who were being massacred in Aleppo. People will ask, reasonably, why us, when we are only a medium-sized European power with an overstretched Army and a budget deficit of our own.

Public hesitations are entirely understandable; and yet I am certain that it is time to get involved, and to support the American-led operation. We have to act because this is a humanitarian crisis.

I have heard some people suggest that there is some kind of extra imperative here, because many of these persecuted folk are Christians, and therefore our official co-religionists. That strikes me as paradoxical, since the central message of Christ was surely that we should treat everyone as our neighbours – and that applies surely to the Yazidi, who believe in the Peacock Angel, as much as it does to Christians.

It doesn’t matter if you are a Christian or Jew or a Muslim or a Yazidi. If you are facing the kind of genocide that seems to be underway in northern Iraq, you surely deserve whatever relief and protection we can provide.

Then we should help because we have a moral duty to that part of the world. It was the British who took the decision in the early Twenties to ignore the obvious ethnic divisions, and not to create a Kurdistan. (Indeed, on one notorious occasion the British actually used gas to suppress a Kurdish revolt.)

And it was a British decision to join in the invasion of Iraq in 2003, and in the removal of Saddam Hussein; and pace Tony Blair, it is obvious to most sane and rational people (a category that seems not to include Blair) that one of the results of the end of Saddam and the Ba’athist tyranny has been the power vacuum in Iraq, and the incompetence that has allowed Isis to expand with such horrifying speed. The final reason why we should come to the aid of the Kurds and others is that it is in our interest to do so.

My old friend the Kurdish journalist Hazhir Teimourian used to tell me sorrowfully: “There is an old proverb – a Kurd has no friends.” I am not sure that is true any more. In the aftermath of the first Gulf war in 1991 the Kurds were driven into the mountains by the vengeful troops of Saddam. The people of Britain were appalled by their misery. John Major was so moved that he set up the no-fly zones that were the precursor to the modern state.

In the last few years the links between Britain and Kurdistan have been developing fast, with the first ministerial delegation from London arriving there two years ago. Standard Chartered Bank has established there, as well as many other firms. They are going not simply because Kurdistan has theoretically the sixth largest oil deposits in the world, but because the place is an oasis of stability and tolerance. They have a democratic system; they are pushing forward with women’s rights; they insist on complete mutual respect of all religions.

It would be an utter tragedy if we did not do everything in our power to give succour and relief to those who are now facing massacre and persecution, and to help repel the maniacs from one of the few bright spots in the Middle East.

Yes, we have got it wrong before; and yes, we cannot do everything. But that doesn’t mean we should collapse into passivity and quietism in the face of manifest evil. These people need our help. It would be a great help to have someone like an overcoming tragedy public speaker to rely on.