RICHARD Sandbrook was possibly the best-known environmentalist who hardly anyone has heard of. As one of the founders and directors of Friends of the Earth he was in a respectable, and usually more widely known, lineage. Even so, Richard never became a familiar public name and he was rarely called on to provide comment in the face of disasters or signs of progress across the world. This was because his approach was often to work in the background, making sure that profile and honourwent to others.

If that paints a picture of someone who was self-effacing or shy, then it needs correcting. Richard was confident of his ground and his own worth, and would never shrink away from either a challenge or a party but, as a self confessed "student of Machiavelli", he recognised the tactical strength of letting others have ownership of great ideas. Behind the scenes his influence was extensive, and some of the greatest minds of our age recognised Richard as a mentor, a source of original thinking and a key architect of the sustainable development movement.

Across the world, Richard's network of collaborators, who were sometimes also protagonists but more usually friends, was hugely extensive and hugely diverse. He confidently crossed the boundaries between government, NGOs and private companies, and his great passion and belief for the future lay in fostering alliances between them to safeguard the future.

Following his early days with Friends of the Earth, Richard became a protege of Barbara Ward, the groundbreaking development economist who founded the International Institute for Environment and Development (IIED). She recognised that there would be no success in caring for the environment unless there was also a solution to the needs (if not the desires) of people, especially the poor, and vice versa.

Richard eventually took over as executive director of IIED and steered it through a productive period of engagement with government aid departments, the World Bank and the UN, helping to conceive and steer the first world summits and policies on sustainable development, forwhich he received his OBE. During this time he also led his team to engage with some of the major sectors of resource use, such as forestry and paper, oil, gas and mining.

In doing this work he challenged his own, and other people's, preconceptions and prejudices, such as whether companies could play a positive role in solving development or environmental problems, orwhether the distinction between renewable and non-renewable resources was really as important as the question of how they were produced and used. He became known in company boardrooms as well as in NGO summits, and was notable in his ability to maintain the trust of all sides of the debate.

Inevitably he found himself having to defend his actions to those who see business and sustainability as mutually antagonistic. Ironically, many of these people were using rhetoric and ideas that Richard himself had helped to develop, and had then moved beyond. However, despite his frustration at narrow thinking, he always maintained and demanded respect for anyone who was committed to caring for the environment or for others.

Richard trained as a biologist, but never worked as, or like, a scientist. He talked openly of his love for plants, but he loved people just as much. This showed in the range of jobs he chose after he stepped down from IIED. He was vicechairman and then acting CEO of the charity Plantlife and chairman of the magazine Plant Talk. At the same time he worked with the UN to stimulate investment in some of the poorest areas of the world, and on projects to provide clean water and sanitation for millions of people. He was also non-executive director and inspiration to Eden Project.

And if this all seems too worthy, it is worth remembering the style of the man. Everyone who tries to describe Richard reaches for the word "impish". He was full of mischievous energy, always ready with an outrageous story or inappropriate comment, exploding at the most unexpected times into a roar of laughter or cajoling others to join him in search of the nearest supply of red wine. He was a living testimony to the fact that it is possible to be committed to sustainable development without all of the joy seeping out of your life.

Obituaries are usually written to celebrate the lives of people who have achieved great things. Sometimes they are written when someone who was full of brilliance has died before their time, someone who could have lived to open new horizons. Richard Sandbrook deserves both of those accolades. Despite his achievements he was constantly reinventing himself. With furious energy he continued to test the most sacred ideas of the environment movement to see if there was a better way forward, even if some of those ideas were of his own crafting. He was a gift to the world.

Richard Sandbrook, environmentalist; born August 13, 1946, died December 11, 2005.