People are seen near a bus destroyed by an airstrike that killed dozens of children, on August 12, 2018 in Saada, Yemen.

© 2018 Mohammed Hamoud/Getty Images

Investigating the terrible toll that the war in Yemen is inflicting on civilians has become, sadly, a regular occurrence for human rights investigators.

We and others have documented scores of unlawful airstrikes by the Saudi-led coalition that have killed hundreds of civilians in Yemen. We have shown that the coalition’s blockade makes it harder to get vital humanitarian aid into the country. And we have sounded the alarm that the coalition, and the Houthi armed group it’s fighting, are accelerating the country’s march towards catastrophic famine.

But then came last week’s deadly airstrike on a bus filled with children.

At least 21 boys were killed when coalition forces struck the vehicle in Houthi-held northern Yemen. Another 35 were wounded. One distressing video shows a very young boy being treated at a hospital. His face is bloodied, his clothes torn, his face a picture of blank bewilderment. He is still wearing a tiny blue backpack.

This video, awful as it is, shows all too clearly the cost of Yemen’s war on civilians. But the attack also shows the callous indifference of the Western powers enthusiastically arming the coalition. How have the United States and the United Kingdom, who have sold billions in arms to Saudi Arabia since the war began in March 2015, reacted to this incident?

Have they suspended their arms sales to the coalition? They have not.

Have they demanded United Nations sanctions on coalition leaders commanding the forces responsible for repeated laws-of-war violations in Yemen? They have not.

Instead the UK government spoke of its “deep concern” about civilian deaths, while the US says it’s sufficient for the Saudi-led coalition alone to investigate the attack. This is the same coalition that has failed time and again to credibly investigate its own allegedly unlawful airstrikes and, contrary to UN and human rights groups’ findings, has repeatedly found no evidence coalition forces violated the laws of war.

If key arms suppliers are genuinely intent on minimizing civilian harm in Yemen, this horrific incident should mark the point of no return. Weapons sales to Saudi Arabia should be immediately suspended. And the UK government should say publicly that these continued apparent war crimes necessitate the renewal and strengthening of the mandate of the Group of Eminent Experts on Yemen – charged with investigating violations in the country – at the UN Human Rights Council this September.

If the deaths of so many children in a single day doesn’t stir the conscience, what will?