Lord Coe's apparently steady hand on the London Olympics' tiller has faltered. His robust defence before a Commons committee earlier this month of the controversial acceptance of £7m in sponsorship from Dow Chemical now seems like bluster.

The multinational refuses to acknowledge any liability for the world's worst environmental disaster at Bhopal in India in 1984, despite now wholly owning Union Carbide, the chemical plant's principal owners at the time. The victims, dead and disabled, are now numbered in hundreds of thousands, and Dow is being pursued through the courts for compensation. The company's reputation in India is understandably tainted, and unless Dow's sponsorship is rejected, in nine days' time the Indian Olympic Committee will hold a vote on whether to boycott the London Games.

The withdrawal from participation on such grounds of the world's second largest nation, a country with which we have strong historic and continuing ties, cultural and economic, would be a grave injury both to the Games and our international standing. A groundswell of voices including the shadow Olympics minister, Tessa Jowell, a member of the organising committee, is now with good reason calling for the deal's cancellation. Sport must trump sponsorship. Lord Coe must refuse Dow's money.