The growing row over Dow Chemical’s sponsorship of the London Olympic Games threatens to derail the election campaign of the capital’s Conservative Mayor Boris Johnson after the local Indian community, a significant voting bloc, on Thursday threw its weight behind the campaign for the deal to be scrapped and criticised him for his pro-Dow stance.

In a rare show of unity, representatives of the Hindu Forum of Britain, the Muslim Council of Britain and the National Council of Gujarati Organisations came together to oppose the deal protesting Dow’s links with the Bhopal gas tragedy and its refusal to take moral responsibility for the liabilities it inherited from Union Carbide.

Besides a £7 million deal under which Dow is funding a fabric wrap for the Olympic stadium in east London the company has a ten-year sponsorship arrangement with the International Olympic Committee estimated to be worth at least £100 million.

Mr. Johnson’s strategists are desperately trying to woo London’s estimated 500,000-strong Indian community ahead of the mayoral elections in May. But his strong backing for Dow has angered Indian voters handing advantage to his Labour rival Ken Livingstone who has attacked the deal and said that the company should be “kicked out” of the Games.

Navin Shah, a member of the London Assembly, said that he had “warned” Mr. Johnson that he risked losing Indian votes if he continued to back the deal.

“My constituency in Brent and Harrow has one of the highest Indian populations in the country. I have been warning Boris Johnson for six months that the Indian community will not accept Dow being part of the Olympics in their home town. Boris has shown that he is not concerned how the Indian community feels about their Olympic games,” he said.

Bharti Tailor, Secretary General of the Hindu Forum of Britain, said that while his organisation supported the Games and was helping with arrangements it had “moral and ethical” objection to Dow’s sponsorship. Dow, she said, must be held responsible for the liabilities of Union Carbide.

“If we do not hold commercial organisations responsible for their actions, they will continue to trample over society,” she said.

Mr. Johnson has strongly defended Dow’s involvement questioning claims that Dow owed responsibility for the Bhopal tragedy.

"I think it would be a shame if you were to persuade LOCOG (London Organising Committee of the Olympic Games ) to get rid of something that would be of great advantage to the Olympics and will serve as an extra attraction to the stadium," he said.

Mr Livingstone, on the other hand, has said that Dow’s sponsorship will "undermine" the spirit of the Games.

"It would undermine London 2012 to take money from a sponsor that refused to clean up its own subsidiary’s mess. It is not too late to prevent the damage. LOCOG and the Mayor should admit that they have made a mistake," he said.

Barry Gardiner, a senior Labour MP and chairman of the Labour Friends of India, described the Indian community’s move as a boost to the campaign to "kick Dow out".

"Boris Johnson and the Conservative Government have made it clear where their priorities lie. They have lined up with a multinational company with a long history of business malpractice and against the victims of Bhopal and the 500,000 people of Indian origin who live in London," he said.