The threat of a consumer embargo is a more powerful driver of "corporate environmentalism" than green marketing or government regulations, according to an economic professor.
In findings published in the Economic Journal of the Royal Economic Society, Professor Robert Innes says boycott leaders have become increasingly sophisticated in their tactics.
"Boycotters carefully design their campaigns in view of the known susceptibilities of a potential target - its reputation, financial position, prominence in the public eye and propensity for responsiveness," he said.
After studying boycotts, mainly in the US, and constructing economic models of different scenarios for action, he has produced a recipe for success.
Successful ones included campaigns by rainforest action groups that led 400 large retailers and timber users to phase out all wood from old forests in favour of sustainable versions.
Boycott threats from Greenpeace forced Burger King and McDonald's to ensure that their products were free of genetically modified content. They also factor in the visibility of their message to consumers and the level of brand identification with the public.
Professor Innes says the key issue for protest groups is how they can play one company off against another to get them to comply. His findings include: a protest group should invest heavily in a campaign if the target is a large corporation; a boycott threat at two companies can make both sign because each will fear the other will sign, allowing it to take trade from the boycott-hit firm; where there are large and small companies, campaigners should target the large ones first - if it gives in, that delivers bigger benefits, while if it does not, its smaller rivals will give in to steal its trade.
Professor Innes also says that a boycott against a small company is a waste of money as the cost to it of giving in probably outweighs the gains, so it will sit tight. This will encourage larger firms to do the same.
Boycotters should target areas where consumers get their highest personal satisfaction from buying "green" goods and where the cost to the firm of changing its policy is lowest.
On the other hand campaigners are unlikely to win against firms that take pre-emptive pro-green moves - even if less than the protesters want - because public support will be weaker. Boycott threats are more effective than lobbying for government regulation, he adds, because sabre-rattling is free, while lobbying MPs is costly.Reuse content