Protests by milk producers in Europe continue to gain strength. A number of farmers organisations in Switzerland have joined their colleagues in Germany, Austria, the Netherlands and Belgium in staging delivery boycotts, claiming the prices they receive for their produce are too low as Martin Haab of the Swiss Farmers group makes clear: "Costs have risen sharply in recent weeks and months and we have not been successful in negotiating a higher price with dairies for the summer," he said.

The farmers are demanding 40 euro cents per litre of milk, an increase of five cents over current prices. They claim that sharply increased diesel fuel costs and the higher price of animal feed are hitting them especially hard.

The boycott has reportedly not yet had any notable effect on supplies at supermarkets, but that situation could change as the boycott grows.

Demonstrating their frustration with the situation some dairy farmers in the Netherlands have poured their milk supplies onto their fields.