Douglas Learmond, right, with the US trade representative Robert Strauss at Gatt talks in 1978

Douglas Learmond was a journalist of the old school. By 1976, the year he was headhunted to join the commodities desk of Reuters, he was already a thorough expert on the market for such items as oil, silver, copper, base metals, coffee, cocoa and sugar.

He absorbed every aspect, from production to prices — from how coffee was grown in the Blue Mountains of Jamaica to how unexpected snowfall in Florida would affect the market price of frozen citrus. Unassuming about his wealth of knowledge, Douglas was nonetheless respected for his expertise. One leader of high-ranking trade talks refused to report their conclusions “until Douglas Learmond is back in the room”.

In the 1970s and 1980s, deals were still cut on the trading floors rather…