Around £3bn is needed from the government's coffers to support farmers with restoring the environment once the UK leaves the EU, charities say.
The UK currently spends around £3.2bn a year on both farm income support and environmental payments under the EU Common Agricultural Policy (CAP).
Conservation charities RSPB, National Trust and the Wildlife Trusts say this amount must be rolled over post-Brexit to support 'nature-friendly farming'.
A 'long-term financial commitment' is needed to pay farmers if they are to help the government meet its commitments to recover the natural environment and address the climate crisis.
Michael Gove first announced the government's 'green Brexit' plans last year when he was Defra Secretary.
He set out plans to scrap the CAP, which he called 'environmentally damaging and socially unjust'.
Under the new direction, farmers will be rewarded for planting wildlife habitats, woods, wildflower meadows and other environmental benefits.
But the RSPB, National Trust and the Wildlife Trusts have today (19 September) urged the government to re-invest the current annual UK CAP budget to help farmers restore nature and tackle climate change on their land.
The groups have released new evidence to develop an understanding of what investment this will cost to deliver.
They say £3bn is required to pay for the recovery of farmland wildlife, enhancing habitats, protecting soils and cutting greenhouse gas emissions.
Patrick Begg, of the National Trust, says farmers need the 'certainty and security' of long-term funding.
“We hope that ministers will take it on board and guarantee this money for farmers not just for the next one or two years, but at least the next decade.
“The Agriculture Bill must also be reintroduced to the next session of Parliament, so we don’t lose the progress that’s already been made.”
How much will this cost?
Initial research commissioned by the three charities in 2017 showed that at least £2.3bn would be needed to achieve the UK’s environmental land management priorities.
This has now been updated to reflect the latest data and to take into account other factors, such as the costs of providing supporting advice and to lock-in the public goods associated with long-term land use change.
The new research suggests that at least £2.9 billion a year is needed – this is just under the current annual UK CAP budget.
In a statement, the charities said: “It is important to note that the research relates to the costs associated with government support for nature-friendly farming.
“It does not cost everything we need to do across the UK to recover our natural environment and achieve net zero carbon across all sectors.
“Crucially, this research demonstrates that supporting nature-friendly and climate-friendly farming is affordable.
“We can re-invest the public money already spent on farming to deliver public goods whilst nurturing a sustainable and resilient farming and land management sector.”