Named after their creators, the Brock contained potassium chlorate, a flammable liquid, while the Buckingham was filled with phosphorous to act as an incendiary.

Six of the trains cars fell into the water, but it was carrying chlorate, oil and sodium hydroxide and nobody was hurt.

These chemicals were mainly ammonium-nitrate fertilizer or potassium chlorate shipped from China for use in Pakistan’s match industry and then smuggled across the border.