Companies that continue to do business with Zimbabwe have defended their stance this week, saying – just as Tesco originally did – that withdrawal would harm the people who depend on them for their livelihoods and products. They include Waitrose, the grocery chain that is part of the UK’s John Lewis Partnership, which imports fair-trade tilapia from a fish farm on Lake Kariba.

Its supplier, called Lake Harvest, employs 450 people, paying them “substantially more” than the minimum basic wage, according to Waitrose. They are also given other cash allowances, free lunches and HIV/Aids support, with medical insurance and membership of pension schemes for permanent employees.

Waitrose says 60% of the fish are sold locally at cost, while the remainder are exported to earn the valuable hard currency needed to keep the farm operating. Lake Harvest was started in 1997 with the help of the UK government’s CDC, which at the time promoted businesses in Africa.

John Houghton, mayor of Kariba and a member of the opposition Movement for Democratic Change, has defended the fish exports as essential to keep prices down for local sales. “We, the people of Kariba where the fish are farmed, are grateful to Waitrose for their contribution to our wellbeing,” he said this year. Nationally, even after boycotting the violence-ridden presidential run-off last month, the MDC has avoided calling outright for ­sanctions.

That allows companies such as Unilever to defend retaining their presence – in its case a consumer products factory outside Harare, which employs fewer than 300 people and is lossmaking. “We have been in Zimbabwe for 60 years and there has been no request to withdraw from inside the country,” the Anglo-Dutch group says