Chancellor Philip Hammond has pledged to guarantee billions of pounds for regeneration projects at risk because of Brexit, including agricultural schemes.
Local councils and business leaders had protested that Brussels cash for vital schemes to boost environment and agirculture was all in jeopardy.
Last month Cornish business leaders came together to lobby ministers, warning that "vital" local infrastructure projects will be put at risk if EU investment in not guaranteed.
"Anecdotally we hear of businesses postponing investment decisions," Hammond told BBC Radio 4's Today program on Monday at his Conservative Party’s annual conference in Birmingham, central England.
"If we don’t intervene to counteract that effect in time, that will have an effect on jobs."
Mr Hammond's announcement means farmers who made applications for the Countryside Stewardship scheme will be assured of funding.
He said: "I’ve already guaranteed the funding for projects signed prior to this year’s Autumn Statement.
"Today, I can go further. The Treasury will offer a guarantee to bidders whose projects meet UK priorities and value for money criteria that, if they secure multi-year EU funding before we exit, we will guarantee those payments after Britain has left the EU."
'Crucial step'
Country Land and Business Association President Ross Murray said they have been calling for the government to make these commitments.
"This is a crucial step in the transition to a strong post-Brexit future both for the environment and for rural businesses.
"EU funded schemes are vitally important to driving investment in our rural economy and delivering environmental benefits such as creating habitats for wildlife and reducing flood risk.
"The Chancellor’s announcement has made clear that applications made to carry out environmental improvement work under the EU Countryside Stewardship scheme, for example, will be considered and where approved funded until the contract completes.
"Agreements under the Countryside Stewardship scheme usually run for five years and landowners and farmers can now apply to deliver this type of environmental work with the confidence that the agreement will be honoured until its completion."
"While this is an important and welcome announcement, there are still crucial decisions to be made for the longer-term.
"We are urging Government to commit to working with farmers and land managers to establish a fully funded, world-leading domestic Food, Farming and Environment Policy.
"This should be designed to ensure a resilient farming sector alongside work to protect and enhance the environment, and it must be in place ready to succeed and better the EU Common Agricultural Policy from 2021."
