The way the large supermarket chains treat their dairy suppliers is little short of disgraceful, according to a leading Westcountry producer.
The big multiples behaved like "legalised thieves", Roger Jenkin told a group of 40 farmers and agricultural industry professionals after they toured his brother's Cornish dairy farm.
"These supermarket chains hide behind statistics," said Mr Jenkin, the West Cornwall dairy representative for the National Farmers' Union (NFU).
One large chain received dairy products from 2,800 farmers, who were poorly paid, but any negative publicity was fended off by claims about how well it treated the 700 farmers on its own direct-supply producer group, he explained.
"They can claim to be right behind their producers, but of course they are simply not," said Mr Jenkin, who farms near Helston.
But he told his audience that the new dairy voluntary code of practice was "just a good start" on the road to fairness throughout the dairy supply chain.
It had been agreed by the Dairy Coalition of farming organisations with the producers' group and should be given a chance to succeed, said Mr Jenkin.
The meeting, at the farm of Mr Jenkin's brother Philip, at Mawgan-in-Meneage, was organised by the NFU to show the problems and challenges facing progressive dairy farmers and the benefits they produce for the nation.
It involved a tour of the farm and an explanation of the present dairying system, with a herd of 380 Holstein cattle, now using a paddock-grazing system for the milkers.
But as costs continued to rise, the rewards were just not forthcoming, said Philip Jenkin.
His enterprise had shifted from milking Friesians to Holsteins to increase output, but as a breed they were more difficult to handle and returns had certainly not improved.
In 1995 he was being paid 26p per litre for his milk and now he was getting 26.3p he said. In that time feed costs had nearly doubled – and diesel fuel had risen from just 8p a litre to 65p. "In real terms we are certainly worse off, " he added.
"Retailers take 49% of the margin, the processors 17% and the poor farmer, who does all the work, just 34%.
"The retailers are simply taking the mickey out of us. It takes us a month to be paid for our milk – they're getting their money back from their customers in two or three days."
But the British Retail Consortium (BRC), which represents the large supermarket chains, said the dairy voluntary code would make a notable difference to the farmers' trading situation and bring greater transparency.
Andrew Opie, the BRC's director of food and sustainability, commented: "The voluntary code between dairy farmers and dairy processors will give more certainty to dairy farmers – and back up the support that retailers have demonstrated through their own supply chains."