An interview was broadcast on Friday, the 20th anniversary of the gas leak from the Union Carbide factory in Bhopal which killed more than 3,500 people and injured over 100,000 others.
The BBC World programme, which broadcasts news 24 hours a day, wished to cover the anniversary, and had asked a researcher to arrange an interview with Dow Chemical, which took over Union Carbide in 2001.
According to reports, the researcher looked on-line, and found contact details on a web site purporting to relate to the chemicals company. But the site was a fake, set up by on-line activists The Yes Men, mischief-makers with a reputation for targeting big business and international agencies, including the World Trade Organisation.
And so Jude Finesterra, the Dow representative who turned up in the BBC's Paris studio on Friday morning was in fact an impostor. And the announcements he made in the live broadcast interview, claiming that the company was taking responsibility for the disaster and was setting up a $12 billion fund to compensate victims, were not true.
It took two hours for Dow Chemical to hear of the announcements, by which time the interview had been broadcast twice. The BBC immediately released retractions of the interview.
"This morning at 9.00 and 10.00am (GMT), BBC World ran an interview with someone purporting to be from the Dow Chemical company about Bhopal," said the BBC in a statement. "This interview was inaccurate, part of an elaborate deception."
"The person did not represent the company and we want to make clear that the information he gave was entirely inaccurate."
The BBC has apologised to Dow and has launched an internal inquiry.
The hoax has been criticized for raising and dashing the hopes of victims of the tragedy on the anniversary of their ordeal.