Taking his jambiya, a Yemeni ceremonial dagger, from his belt, he cut away a plastic sheet to reveal the twisted skeleton of the bus, which now rests next to the children.

He was dressed in what passes for a uniform in northern Yemen’s volunteer army: tattered blazer, cloth skirt, a tan ammunition belt around the back of the waist and a jambiya, or ceremonial dagger, hanging in front.

He took a length of tubing from his trunk, cut off the end with his jambiya and then, after sticking one end in the jug, sucked on the other end to bring the gas out.

I was struck instantly by his appearance: he wore no belt or jambiya, the traditional dagger Yemeni tribesmen always carry on their belts.

He was in full tribal regalia — a gray suit jacket over a light green tunic, a large jambiya sticking out from his belt, and an AK-47 over his shoulder, which he never removed.