The case had hinged on whether wild camping was considered as "open-air recreation" and led to protracted debates in the appeals courts over closed tents and whether sleeping was deemed to be an activity.

Alexander and Diana Darwall brought the successful legal challenge against Devon's Dartmoor National Park Authority (DNPA) in January, claiming some campers caused problems to livestock and the environment.

But lawyers for the DNPA said the case had rested on a narrow definition of open-air activities such as walking, horse riding and picnicking. They said the ruling could prevent activities such as birdwatching and stargazing.

In the Court of Appeal ruling on Monday, Sir Geoffrey Vos said: "The fact that a tent is closed rather than open cannot convert the wild camping from being an open-air recreation into not being one.

"In my judgment, that walker is still resting by sleeping and undertaking an essential part of the recreation."

Dartmoor became the only place in England that wild camping is allowed without permission from landowners following a piece of legislation in 1985, under which "open-air recreation" is permitted if one enters the common on foot or horseback.

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Monday's appeal decision was welcomed by the Open Spaces Society, which intervened in the case.

Its general secretary Kate Ashbrook said: "This is an excellent outcome. We are relieved that the judges ruled unanimously and conclusively that open-air recreation includes backpack camping on the commons."

"Following this judgment, Dartmoor remains one of only a handful of places in England where there is a right to backpack camping without the landowner's permission.

"We should like to see that right extended and we shall campaign with other organisations to achieve this."

Dartmoor National Park, designated in 1951, covers a 368-square mile area that features "commons" - areas of unenclosed privately owned moorland where locals can put livestock.

The DNPA previously said backpack campers could access nearly 52,000 acres of common land across the national park and could stay overnight under a new "permissive system", as long as they followed a code of conduct.