The year was 1992, just six months after the collapse of the Soviet Union and when the ink was barely dry on the European Union treaty.

Preston’s “Earth increment” – unveiled at the Earth Summit in Rio de Janeiro that June - was to provide low-cost environmental loans through the bank’s International Development Association, a complement to the billions in aid promises made to help heal the economic and environmental rifts left by the Cold War.

But Preston’s plan would – like other commitments to help the ecology of disadvantaged nations in the two decades since the Earth Summit – never saw the light of day.