'Off, dog!' cried Hindley, threatening him with an iron weight used for weighing potatoes and hay.

Much of the field work was done hundreds of miles out at sea, and included areas off South America and Antarctica where iron has been introduced as an experiment.

The whole nation is watching closely to see what happens over the next few years as Chengdu takes off the iron collar and breaks down the wall that kept farmers and urbanites separated for so long.