The Labour party will pass a right to roam act if it comes to power, the Guardian can reveal, after widespread outcry when wild camping was outlawed on Dartmoor.

In the bill, which is currently being drawn up by the party amid widespread but careful optimism that the next general election will see Labour return to office, there could be a new law that would allow national parks to adopt the right to wild camp, as well as expanding public access to woodlands and waterways.

Jim McMahon, the shadow environment secretary, said the court decision earlier this month to overturn the long-held right in the national park – the only place in England and Wales the ability still existed – shows that there needs to be a rethink of land access.

While the right to roam has been narrowly defined as the right to walk from A to B, he said this was missing the point and not in the spirit of those who first proposed the idea.

He said: “What I am interested in is the right to experience, the right to enjoy and the right to explore,” meaning that people should be allowed to fully enjoy an area, including taking part in activities such as swimming, camping, climbing and birdwatching rather than simply walking.

Visiting Hay Tor in the national park, McMahon said: “It’s not just about the right to pass through and explore. I think we do need to go beyond that, to look at the enjoyment aspect of it as well, which really hits at the heart of the Dartmoor case. The current right to roam gives people the right to pass through, but what about actually experiencing it, and to enjoy it? Our policy needs to give people more rights to do that.”

As ponies trotted by on the moor, he said a Labour government would create more national parks and open more of the countryside for people to explore.

“There are still huge parts of England and Wales that are off limits when it comes to the right to access, whether that’s woodlands, cliffs, rivers, where the rights that we are afforded in open countryside aren’t then mirrored in those places. That needs to change.”

Only 4% of waterways give people an automatic right to canoe or swim, and McMahon plans to significantly expand this in government. He said: “This is a scandal. A Labour government would clean up the UK’s waterways for all to enjoy – if people don’t have a stake in their environment they won’t fight to protect it.”

Alexander Darwall, a hedge fund manager and Dartmoor’s sixth-largest landowner, took the national park to the high court last month, arguing that the right to wild camp had never existed. The judge this month ruled that the right to roam means just that – the right to walk or horse ride on the common, not to camp.

Darwall, the owner of the 1,619-hectare (4,000-acre) Blachford estate on southern Dartmoor, offers pheasant shoots, deerstalking and holiday rentals on his land.

The court case has reinvigorated the right to roam movement, with 3,000 people last weekend travelling to protest on his land.

It’s a hot topic in parliament, too, with Luke Pollard, the Labour MP for Plymouth Sutton and Devonport, calling for a new law enshrining the right to wild camp on Dartmoor.

Caroline Lucas, the Green MP for Brighton Pavilion, has her right to roam bill returning to parliament this spring, and Richard Foord, the Liberal Democrat MP for Tiverton and Honiton, has tabled a bill that would protect the public’s access to national parks.

Foord said: “Wealthy landowners should not seek to move in and overturn the ways in which our national parks have been used.

“If people choose to buy land in a national park, they must accept all the responsibilities that come with it. They should not be seeking to prevent respectful wild camping, or worse still, expecting taxpayer-funded organisations like the Dartmoor National Park Authority to pay the landowners for continued access.”

The park is in talks and deciding whether to risk appealing against the decision to overturn wild camping, which could mean spending vast sums on Darwall’s legal costs if they lose. It has to submit its decision by a week tomorrow.

McMahon called on the park to appeal against the ruling, and said the case showed the right to roam law needed to be clarified and strengthened.

He said: “Part of the reason we’re coming here, of course, is because of wild camping, but the case also poses an existential threat to what we’ve taken for granted, really, which is the access rights that we all enjoy, which were enshrined by the last Labour government in 2000. I think they’re under a fundamental threat if this is allowed to go unchecked. So then, the law needs to be basically clarified and strengthened.”

McMahon said a Labour government would enshrine the right to wild camp on Dartmoor in law if there was no successful appeal. He said: “Ultimately if an appeal isn’t successful, it isn’t right that this right can be taken away by one landowner. So it’s parliament’s job to make sure it is enshrined in law.”

Campaigners have asked the park authority to appeal. Lewis Winks, from the campaign The Stars Are for Everyone, said: “Dartmoor was the only place in England where the right to wild camping existed. We don’t want this to become a quirky historical anomaly, we want to see the same rights afforded to people in other national parks, so what happens today is of crucial importance to the newly reinvigorated right to roam movement. We need Dartmoor national park to step up and be courageous.”

In a statement, the Right to Roam campaign said: “We welcome the Labour party’s commitment to legislating for an expanded right to roam as part of their programme for government and look forward to engaging with them on the details.

“Last week’s historic protest on Dartmoor, attended by 3,500 people – following on from a year of mass trespasses organised by the Right to Roam campaign – demonstrates the huge public appetite for increasing access to nature.

“We call on MPs of all parties to publicly support a right to roam act to defend and extend the rights of all people to access nature.”