Zambia’s economic development since the 1920s has been heavily dependent on copper mining. 60% of the country’s export earnings come from copper, amounting to 10% of GDP, and last year it was on track to export one million tons of the metal, much of it destined for electric cars.

When the Zambian government privatized the mining industry in the 1990s following economic decline and pressure from foreign donors, a steady stream of investment started to flow in. But rather than being swept up in a tide of prosperity, Zambians living around the mines have experienced a deluge of toxic chemicals, discharged into the air and water.

When Mufulira District Commissioner Beatrice Mithi died after inhaling sulphur dioxide released by Glencore subsidiary Mopani Copper Mines, her widower sued the company. In September 2016, he was awarded 400,000 Zambian kwacha (£30,000) in damages by the country’s highest court.

Previous similar cases against other firms have been less successful. In 2011, the high court in Lusaka ordered mining giant Vedanta and its Zambian subsidiary KCM to pay about £1.3m to 2,000 people, after the Chingola mine discharged sulphuric acid and other chemicals into a tributary of the Kafue River in 2006. When the company appealed the ruling, the Zambian Supreme Court upheld the judgement but reduced the compensation order to almost nothing.

As the problems continued, farmers from the Shimulala Hippo Pool, Hellen and Kakosa villages-who say that their water source was turned into a river of acid when mining chemicals spilled into it-decided to take their legal battle to London.