More than 40,000 large dams now regulate the world's rivers: some have been built to generate hydroelectricity, others to provide irrigation water, and others as part of flood control programmes. These large-scale construction projects have invariably caused considerable human suffering and environmental damage.

Dams built to generate electricity are said to provide a cheap, reliable and economic source of power, but over-optimistic assessments of power outputs have made many of them “white elephants” – expensive and useless – that leave Southern countries with large debts, which poorer people invariably end up paying for through cuts in public expenditure on health, education and other public services.

The Corner House has used its knowledge and experience of large-scale dams to support people affected by the proposed Ilisu Dam in Turkey, Lesotho Water Highland Development Project, and the Merowe Dam in the Sudan, among others.