Friends of the Earth, the World Wide Fund for Nature, Mr Lees' partner, Dr Christine Orengo, and the broadcaster and naturalist Sir David Attenborough pleaded with the British mining giant Rio Tinto Zinc to abandon its plans for 40 years of mineral extraction in southern Madagascar.
The titanium dioxide mining would destroy most of the remaining pockets of a unique endangered forest. Mr Lees died there from a heart attack on New Year's Eve while he was investigating the project.
Sir David Attenborough said: ``I've travelled in these forests and I know what amazing wonders they contain. I'm convinced it would be economic folly to exchange something that would bring revenues from ecotourism in perpetuity for a payment [from mining] that will end within 40 years.''
Dr Orengo, who flew out to Madagascar earlier this month to join the search for Mr Lees' body, was at yesterday's London launch of the campaign. ``Andrew's loss is not just a tragedy for me but for the many people whom he inspired and who loved him,'' she said.
Yesterday, it also emerged that RTZ is being sued for negligence by a former employee, Edward Connelly, who claims he was poisoned by toxic uranium dust while working at a uranium mine in Namibia owned by an RTZ subsidiary, Rossing Uranium. Mr Connelly, a fitter, blames his throat cancer on failure by the company to protect him from the dust during five-and-a-half years at the open-cast Rossing mine.
If Mr Connelly is successful in his legal action against the company it could face other large damages claims from workers who believe their illnesses could be related to the uranium processes at the plant. RTZ is contesting his claim.
Meanwhile, Rossing and another RTZ subsidiary, Richards Bay Minerals in South Africa, received awards from the Chancellor, Kenneth Clarke, yesterday for promoting development in poor countries. Friends of the Earth supporters protested outside the awardsceremony in London.
The campaigners have written to RTZ, the President of Madagascar, Albert Zafy, and Baro-ness Chalker, Britain's overseas aid minister, to condemn the titanium dioxide project. They argue that it would destroy a unique ecosystem, possibly cause several species to become extinct and destroy the livelihood of farmers and fishermen who live next to the forest and use its resources. British taxpayers could eventually contribute to the mining project as part of the overseas aid effort, the Overseas Development Administration confirmed yesterday. The African Development Bank, partly owned and supported by Britain, is a potential lender towards the start-up costs.
RTZ said there were several hurdles to jump before it decided whether to go ahead with the titanium dioxide mining project in partnership with the Madagascar government. It wanted to collaborate with environmental groups to minimise environmental damage.