More than 500 people have attended a mass trespass in protest against new charges to access Cirencester Park, one of the country’s largest open green spaces.

Cirencester Park, in the Cotswolds town, spans more than 3,000 acres and has been free to access for members of the public for 326 years.

But the Bathurst Estate, which has owned the land since 1695, say fees must now be introduced to maintain the cost of the parkland as well as new facilities on the site.

Visitors are now charged £4 per adult, while those living in Cirencester or in nearby villages can pay a £10 deposit to access the park.

On Sunday, local residents and protesters from across the West Country walked through Cirencester Park’s main gates on Cecily Hill – which were open – as part of a mass trespass.

They chanted “Whose park? Our park”, with some holding placards reading “Right to roam”. Other signs included one reading “The peasants are revolting” and “Nature should be for everyone, not just for those that can afford it”.

Jon Moses, organiser of campaign group Right To Roam, said the park land was bought by Benjamin Bathurst with profits from the transatlantic slave trade.

Mr Moses said a price had been already paid for the park over the years, including by the slave trade, lost local transport links, and government agricultural subsidies.

“All that has been asked in return for these multiple extractions is that the park remain what it has always been – a community space, an open space, a free space available to everyone,” Mr Moses said.

“And now, even that must pay. None of us are responsible for our ancestors, the Bathursts are not responsible for theirs.

“But you cannot profit from a legacy while refusing responsibility for its origin. Nor is it the responsibility of a democratic society to continue bearing its cost.

“Yet here we are, expected to pay once again. Pay in cash just to enter, pay in dignity, expected to carry a photo ID just to go for a stroll, to pay in joy as our way to the wider countryside is shut away, and pay in safety as commuter routes are forced on to roads, your kids unable to wander to school without remembering the household pass.

“Our simple message to the Bathurst Estate is this: If the Bathurst Estate cannot continue to meet its obligations to the park, and there is no room in their annual accounts for its maintenance, then fine, we accept, we’ll take it.

“Please, by all means, give it back.”

People don’t like change, I don’t like change, but unfortunately to keep the park running we have to have some change in here

Right To Roam said the Bathurst Estate listed total equity of £29 million last year, and holds an offshore trust in Bermuda.

Resident David Watts, who regularly uses the park for exercise, said local people “just want to walk in the countryside free of charge”.

Mr Watts said there were historical rights of way through the park, with the main turnpike going up the main path towards the Gloucestershire town of Stroud – until it was bought by the Bathurst family.

“People say, isn’t it reasonable to ask people to make a small contribution, the bins have to be empty and the grass has to be cut, all of that costs money,” he added.

“Some people say it’s reasonable and it’s not a lot of money. Well for me, it’s not really about money. It’s about the freedom to walk in the countryside.

“But if we want to talk about money, let’s talk about the wider Bathurst enterprise, which is built out of the slave trade.

“It is enormously wealthy. It is many different companies, all of which have tens of millions of pounds to them.

“There’s 15,000 acres of land, properties, farms, property development, holiday cottages, cafes, car parks, there’s even a heated dog wash.

“There’s plenty of opportunities to make money without charging people to walk in this park.”

Right To Roam said just 1.2% of the Cotswolds is designated as access land under the Countryside and Rights of Way Act, with the loss of access to Cirencester Park reducing the freely accessible land by more than one third.

Ali North, 33, travelled from Swindon, Wiltshire, and joined those protesting at the park with a homemade sign reading “Right to roam”.

She said: “We are living through a time when access to nature is more critical than it has ever been.

“Having the introduction of barriers, in addition to other barriers people might feel, is a step backwards.”

Leigh Chapman, 76, who has lived in Cirencester for 50 years, brought a sign reading “The peasants are revolting” to the protest.

“The park has fond memories for people who live here – walks with the family, the kids and the dog,” Mr Chapman said.

“It is so close to the town centre and then it is Bathurst land for about five miles.”

Lord Bathurst, who stood by a gate to watch protesters gather in the park on Sunday morning, said the charges are important to maintain the land.

“People don’t like change, I don’t like change, but unfortunately to keep the park running we have to have some change in here,” he said.

“It has changed enormously over the last 20-30 years and it will continue to evolve.

“People might find it unpopular to charge people for coming in, but for local people it is still free for people to come in – they can pay a £10 deposit.

“There are so many other places, National Trust properties, Westonbirt Arboretum, that we have to pay to go into.”