UK supermarkets are increasingly squeezing the price they pay to the poorest farmers and workers in their supply chains, according to a report by Oxfam.
The charity's Ripe For Change report claims supermarkets including Tesco, Sainsbury's, Morrisons, Asda, Aldi and Lidl are squeezing payments to their suppliers, with "less and less" of the price paid at the till reaching small-scale farmers and workers who produce the food.
Oxfam said none of the food supply chains it analysed enabled people to earn enough for even a basic standard of living.
In some cases, like Indian tea and Kenyan green beans, workers were earning less than half the amount they needed to "get by".
The report also claimed that women face routine discrimination, often providing most of the labour for the lowest wages.
Across 12 common food products, including tea, orange juice and bananas, UK supermarkets receive almost 10 times more of the checkout price than the small-scale farmers and workers who produce them, Oxfam's analysis found.
The report includes a scorecard analysis of the six biggest supermarkets in the UK based on international standards and recognised good practice on human and labour rights, with scores ranging from just 1% for Aldi to 23% for Tesco.
Matthew Spencer, director of policy for Oxfam GB, said: "It's shocking that so many of the farmers and workers producing food for our supermarket shelves are going hungry themselves.
"Our biggest supermarkets are squeezing the price they pay their suppliers, resulting in huge, hidden suffering amongst the women and men who supply our food and trapping them in poverty."
Oxfam's report marks the launch of Behind The Barcodes, a global campaign urging supermarkets and governments to crack down on inhumane working conditions, increase transparency on where food comes from, tackle discrimination against women and ensure that a larger share of what consumers spend on food reaches producers.
Mr Spencer said: "Global businesses can help lift millions of people out of poverty, but the food industry currently rewards shareholder wealth over the work of millions of women and men, with supermarkets ignoring the hidden suffering behind their food supply chains.
"When companies get serious about supporting decent work they can help transform lives in some of the poorest parts of the world."
An Aldi spokesman said: "Aldi UK operates with honesty and integrity wherever it does business around the world. We respect human rights and treat the people in our supply chain who make, grow and supply our products fairly.
"We have comprehensive policies and processes in place, based on internationally recognised standards, which protect human rights for workers across our supply chain."