Yet what has this to do with us? There has always been war. It is possible to cause mayhem with a machete or to terrorize with a spear. True, but a child with a machete is one thing. A child with an AK-47 is another. And there is ample evidence to show that the greater the availability of guns, the more people will die and the faster the conflict will spread. If your enemy threatens you with a gun, you will not want to respond with a knife. You will want a gun, too.

Graca Machel, the wife of Nelson Mandela, has seen plenty of war at first hand in her own country of Mozambique. In a report for Unicef she wrote: “Wars have always victimised children and other non-combatants, but modern wars are exploiting, maiming and killing children more callously than ever.” Modern wars are fought with guns.

It is estimated that there are 638m small arms in the world. That’s about one for every 10 people. In much of Africa you can get one for a bag of maize. In Afghanistan an AK-47 will cost you $10. Or you can spend a bit more and buy an automatic from a man in a pub in Birmingham or Manchester or London.

It is our business because it is we who produce them and trade in them. The vast majority of small arms in the world come from Europe, the old Soviet countries and North America. The richest countries in the world export them to the poorest. The global trade is worth $4 billion. But that is only the legal trade. In theory there are “end user” certificates which control the trade in weapons.

They might work reasonably effectively if you want to buy a tank or a long-range missile. But small arms are traded as freely as Coca-Cola. If a British businessman is breaking the law in this country by dealing in small arms, he hops on a plane to France or Germany with his mobile phone and sets up shop there. Nobody knows. Nobody seems to care.

The United Nations acknowledges the “humanitarian dimensions” involved in this trade. The official UN position is that it wants to control

the proliferation of small arms. The slight problem is that there are five permanent members of the Security Council and every one of them is a major supplier.

Southall and his colleagues are campaigning for changes. They want legal arms trading and its regulation to become the responsibility of a newly configured UN, less dependent on the rich arms- exporting countries. The new UN would enforce ethical criteria on the trade. The illegal market would be policed by a new international police force. Illegal arms traders could be charged with crimes against humanity. To all this there is only one realistic response: fat chance.

It is not going to happen. Power is not surrendered. The current UN is an uneasy compromise between the wish of everyone to try to construct some sort of international order and the determination of those with the greatest power to lose none of it. Try to take power away from the powerful and they will simply walk away, just as the United States walked away from the League of Nations which its own president had had the imagination to propose.

This is how it is for idealistic dreamers. They quickly hit the buffers of the way the world really operates. It brings us back to Rumsfeld and to what is possible in a single career. It brings us back to the Scott report and the way politicians in opposition deal with the realities when they find themselves in power. Moral outrage seldom survives hard politics.

So Southall and his well-meaning doctors will achieve nothing and we would be better off if they concentrated all their efforts on curing the sick children in their surgeries and hospital wards? Well, maybe, but I’m not so sure. Practical outcomes should not be the only measure of the value of moral outrage. It is always right to make a fuss about the suffering of the world’s most vulnerable people and the hypocrisy of the world’s most powerful. And somebody may be listening.