Lawyers representing some 750 victims of arsenic poisoning in Bangladesh have won the first stage of a legal battle in London in which they are accusing a British survey organisation of negligence.
The High Court ruled that the British Geological Survey had a case to answer over claims it should have carried out tests for arsenic in a 1992 survey on the toxicity of Bangladesh well water.
The judge, Mr Justice Simon, ruled that the case should go to full trial.
In its attempt to have the case dismissed, the BSG said its survey was part of an irrigation project, and had nothing to do with drinking water.
Some reports suggest arsenic in groundwater in Bangladesh and eastern India has affected millions of people, and caused up to 3,000 deaths a year.
From the newsroom of the BBC World Service