Defra issued the guarantee the government published the first of some 80 technical notices to tell people what to expect in the event of a no-deal Brexit.
In the event that the UK leaves the EU with no deal, Defra said the UK government would fund any remaining payments to farmers, land managers and rural businesses due after March 2019.
This would ensure continued funding for these projects until they finish, said the department.
The guarantee also meant that Defra and the devolved administrations can continue to sign new projects after the UK leaves the EU during 2019 and 2020, up to the value of programme allocations.
If the UK leaves the EU without a deal, Defra said it and the devolved administrations would ensure an uninterrupted flow of funding to farmers, rural businesses and communities.
To ensure stability and continuity, the guarantee would be administered through existing national and local arrangements, modified and simplified as appropriate in line with domestic rules on public spending.
Projects would need to continue to deliver good value for money and meet domestic strategic priorities.
The full technical notice can be downloaded here.
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