An agreement has been reached to allow wild camping to continue in parts of Dartmoor National Park, after a High Court ruling against the right to camp in the protected landscape.

But campaigners hit out at the deal, which they said was a “ransom note” from landowners who would be able to revoke permission to camp at any time – and warned the public would have to pay for what had previously been a right.

Dartmoor National Park Authority (DNPA) said landowners would grant permission to the authority to allow the public to wild camp through a permissive agreement.

Areas where wild camping could take place, without seeking individual permission from landowners, would be shown on an interactive map on the authority’s website in the coming days, it said.

Anyone planning to wild camp must refer to the interactive map and follow all “leave no trace” principles so they have no impact on the area where they have been.

The agreement in principle was secured at a meeting of the Dartmoor Commons Owners’ Association and the National Park Authority.

It comes after two landowners won a High Court challenge against the right to wild camp without permission on the Dartmoor National Park.

Farmers Alexander and Diana Darwall argued that some wild campers on their land caused problems to livestock and the environment and sought a court declaration that members of the public could only pitch tents there overnight with their consent.

Mr and Mrs Darwall, who keep cattle on Stall Moor, which forms part of their more than 3,450-acre estate in the southern part of Dartmoor, secured a finding from a judge that a 1985 law that regulates access to moorland does not provide a right to wild camp.

Dr Kevin Bishop, chief executive of DNPA, which had defended the High Court claim, said: “We have all worked quickly and collectively to ensure clarity is provided.

“Our thanks go to those involved in the discussions who have engaged in this process so positively and proactively.

“We’re committed to working together to continue all our good work that helps keep Dartmoor special for everyone.”

John Howell, chairman of Dartmoor Commons Owners’ Association, said: “We recognise the importance of people being able to enjoy the natural beauty of Dartmoor, including through wild camping, and the benefits that this can bring.”

But following news of the agreement, Guy Shrubsole, from the Right to Roam campaign, said: “This is a ransom note from landowners who will be able to revoke permission to camp at any time.

“As there is no map yet of where wild camping would be ‘permitted’ under this plan, we don’t yet know how many landowners have refused permission.

“The public have just had their right to wild camp summarily snatched from them by a wealthy landowner – now we’re expected to be grateful to landowners who grant us permission to wild camp, and pay for the privilege.”

He said campaigners have been told by the National Park Authority that people would have to pay to wild camp on Dartmoor, though it was not clear whether individuals would have to pay or the DNPA would pay landowners from its publicly funded budget.

He added: “We will not accept any attempts to make people pay to wild camp, and call on MPs to back a new Right to Roam Act to defend and extend public access to nature.”