A new report from Oxfam has revealed harsh working conditions, poverty pay and gender discrimination in British and European supermarket fresh produce supply chains.

Focusing on tea production in India and tropical fruit farms in Brazil, farm workers interviewed by Oxfam spoke of being denied water and toilet breaks, exposure to agro-chemicals and a culture of fear and intimidation.

The charity’s investigation into melon, grape and mango farms in Brazil's Northeast revealed 'widespread and systemic poverty among seasonal workers on fruit farms, particularly women'.

Oxfam said the fruit farms surveyed supplied Sainsbury’s, Lidl, and Whole Foods, and until recently Morrisons, PLUS and Tesco.

They suggested Bolsonaro’s recent election is undoing years of improving working conditions, with the country slipping on International Trade Union Confederation (ITUC) Global Rights Index from one of the best to one of the worst.

Oxfam blamed increased pressure on margins driving supermarkets to take greater share of the value of fresh produce and tea.

“Supermarkets are snapping up the lion’s share of the price we pay at the till - while workers who toil for hours to grow and harvest tea, fruit and vegetables are paid so little they can’t even feed their own families,” said Winnie Byanyima, Executive Director of Oxfam International.

“Supermarkets must open up about where they buy their products fromand they must ensure that their buying practices are not fuelling poverty and abuse, thatworkers in their supply chains are paid a living wage and have safe and dignified working conditions; and that women workers are free from discrimination,” added Byanyima.

Oxfam analysis revealed that supermarkets have increased the share of the price they takefrom a basket of twelve everyday items from an average of 43.5 per cent in 1996-8 to 48.3 per cent in 2015. The share going to workers fell from 8.8 per cent to 6.5 per cent over the same period.

Oxfam credited UK retailers for taking action to improve the supply chain, saying Tesco, Morrisons and Sainsbury’s had committed to doing far more than other “laggard” supermarkets based on the continent.

They accused Aldi North, Whole Foods, and Lidl of lacking robust policies and failing to show the action they are taking to prevent forced and child labour, gender equality, and worker rights protections.

Whole Foods have since rejected Oxfam's claims and said their report used 'selective' information. “Oxfam’s latest report does not accurately reflect Whole Foods Market’s long-standing efforts to address human rights and labor issues in our supply chain, including instituting programs like our Whole Trade Guarantee that ensure fair and safe working conditions for suppliers across the globe,' a Whole Foods spokesperson said.

'We have a proven track record of taking immediate action with suppliers when potential concerns surface and remain committed to supply chain transparency and ethical sourcing, which are areas we continue to invest in. We are disappointed that Oxfam chose to selectively publish the information we provided on our business practices in response to their report, and that they chose not to initially share any level of detail on the allegations made against specific farms.”

Peter Andrews, head of sustainability at the British Retail Consortium (BRC), said: 'Supermarkets in the UK are spearheading actions aimed at improving the lives of the millions of people across the globe who contribute to the retail supply chain.

'Our members are working hard to address existing injustices and continue to collaborate internationally with NGOs [non-governmental organisations], business groups and government on this vital issue.'

Oxfam also interviewed workers in North Carolina harvesting sweet potatoes for Whole Foods who reported working 14 hours a day in oppressive heat with few rest breaks and limited access to toilets.

Workers there also said they are paid low wages and are too scared to speak out for fear of losing their jobs.

The report is linked to another survey from Oxfam released today, interviewing 530 workers across the global food supply chain, showing poverty wages and abuse is rife across the sector.

The survey included 61 workers on Costa Rican pineapple plantations, 104 Ecuadorean workers on banana plantations and 100 Peruvian workers on avocado and asparagus farms.

Three quarters of respondents said they were not paid enough to cover basic needs such as food and housing, as well as lacking safeguarding against injury at work, and were not able to take toilet breaks or drinks when needed.

A Tesco spokesperson said: 'This is the second year in a row that Tesco has been assessed by Oxfam as doing most, of all major supermarkets globally, to ensure human rights are respected in food supply chains.'

'We know there is always more to do and we are working collaboratively with NGOs, trade unions and others to improve wages in the key produce, tea and clothing sectors and ensure working conditions are fair.'

An Aldi spokesperson said: 'We continue to work hard to ensure every person working in our supply chain is treated fairly and has their human rights respected.

'We share the values behind Oxfam's campaign and are in regular dialogue with them.'

In response to the survey, 50 investors with assets worth around $3.1trillion released a statement calling for greater transparency in supermarkets’ supply chains.

“Increased demand for low-cost and high-convenience grocery products from alternative retailers has challenged middle-market grocers, creating a heated acquisition environment for large food retailers to consolidate. This consolidation is concentrating buying power in the hands of a few large food retailers and their major suppliers,” the statement read.

“As the cost of producing food continues to rise, this increased pricing power results in human rights abuses, poor working conditions, discrimination against women, and a declining share of value captured by producers.We recognize that this business model is unsustainable.'