Leave campaigners and Conservative Party donors earned £4 million from EU farm subsidies last year and are set to gain again if the government goes ahead with plans to link any post-Brexit deal with the EU, environmental organisation Greenpeace have said.
Donors to Defra secretary Andrea Leadsom and other members of the Conservative Party gained from the EU policy last year due to their large estates, the organisation said.
Supporters and donors of Vote Leave, could benefit from large pay-outs to their estates, including Lord Bamford and Sir James Dyson.
"As the new environment secretary, Andrea Leadsom has a crucial decision to make for the future of our environment," Greenpeace UK executive director John Sauven told the Huffington Post.
"She can allow wealthy landowners to keep millions of pounds worth of taxpayer farm subsidies or she can use this opportunity to finally sort out this broken system.
"It’s hard to imagine people accepting that money promised to the NHS from Brexit campaigners, including some big landowners, could be lavished instead on the country estates of the super-rich.
"These public funds need to be targeted on helping farmers facing real hardship and in supporting schemes that protect our wildlife, prevent floods and store carbon."
Last month, the group entered into the debate on post-Brexit farm subsidy policy by being a signatory to a letter which urged any subsidy policy to be linked to environmental performance.
In a letter sent to Prime Minister Theresa May, the signatories said better food, farming and trade policies can help cut greenhouse gas emissions within those industries by 80% by 2050.
'We provide thousands of jobs and benefits to the environment'
But in a joint statement to Mrs Leadsom just hours after her appointment, leaders of the UK's farming unions issued a call for the maintenance of subsidies at EU levels.
"We provide thousands of jobs and deliver countless benefits to the natural environment," they said.
"To be able to do this, and more, we are looking to all UK governments to commit to maintaining current levels of farm support."
During their referendum campaigns, Leadsom and farm minister George Eustice said that current levels would be kept.
"I have made it clear that I will guarantee the current level of support under a UK Agricultural Policy," Leadsom told the Countryside Alliance echoing similar statements made by Eustice that countries outside of the EU were able to give more to their farmers than the UK currently does.
Foreign Secretary Boris Johnson told the Treasury select committee that "all farmers will continue to receive the current levels of subsidy, it would be at the level that they currently enjoy and that level of support would be perpetuated."
A spokesperson for the Department for Environment said: "The Secretary of State has been very clear that we now have an unparalleled opportunity to make sure all our policies are delivering for Britain and to grow our world-leading food and farming industry.
"She has underlined the need for continuity for farmers and is looking forward to working with industry and the public to develop new proposals that provide tailored support for our agricultural industry as we leave the EU."
Matthew White Ridley, 5th Viscount Ridley, told Energydesk that the Blagdon estate is a business supporting jobs in Northumberland.
"All CAP subsidies received by the Blagdon estate are re-invested on the estate, including in environmental conservation such as the creation of new flower meadows, new hedgerows and new environmentally friendly field margins, for which the estate has won awards.
"In campaigning for the UK to leave the EU I was arguing in the broader public interest, and against my own immediate interest."