With a "catastrophe" in the world coffee trade and many growers facing starvation, a leading coffee buyer appealed to the International Coffee Organisation in London yesterday for a tax of $1 on a 50kg bag to save farmers.

In a passionate speech Walter Zwald, chairman of the Swiss Coffee Federation, said coffee was the second-largest traded commodity after oil, yet it had a tarnished image and sales were going down, particularly among the young.

"It is a huge and wealthy industry, yet the beans are grown almost entirely by very poor people who receive hardly anything for their labours. I think for once we should not wait until something severely damaging happens." Mr Zwald said the future depended on stability and a tax of $1 a bag, less than a thousandth of a cent per cup, with half to go to growers for improved living conditions, education and stability, and the rest to promote new markets and quality.

Prices have halved to $75 a bag this year, mainly because of a World Bank-financed drive to plant coffee in Vietnam. Production has risen from 4m bags to 16m. Big firms, including Nestlé, Procter & Gamble and Sara Lee, which owns Douwe Egberts, have kept prices up to benefit shareholders while the price to growers has halved.