One campaigner believes the festival in South London Park unfairly cut off most of the space and made it a "muddy bath", winning a court case that could lead to an incident where it was banned this summer.

Protect Brockwell Park (PBP) group, including actor Mark Rylance, complained about the erecting of walls in the park, as well as noise and environmental damage, leading to tense debates about the importance of using public spaces, Nimbyism and summer cultural activities.

Rebekah Shaman, who lives in the area, is a member of the PBP, who has taken legal action against the Lambeth Council, which heard in the High Court this week urging its review to hold a massive event in Brockwell Park.

The ruling could affect events held by Summer Events Ltd, including a large number of sober, powerful Hoopla, Field Day and City Splash, which will be held in the summer.

The challenge is whether the Council decides to prove that the land use is legal. According to the allowed development rules, a total of temporary changes to usage will be allowed per calendar year, but the Brockwell Park Festival is more than 37 days and will begin on May 23.

High Court Justice Moore ruled that the shaman was favorable, saying the Council’s decision to award certificates to festival organizers was “irrational”.

Rylance said victory was “good news.”

"Good news. Brockwell Park will be open to everyone again this summer for free. No walls. No trucks.

“Grass, trees and plants will have a chance to recover from years of abuse.

“Now, let us help restore the former Lambes Country Fair, open to all. Congratulations to all who have worked hard to achieve this decision.

“Every little victory of nature makes a difference.”

"These large-scale, high-impact business festivals are undermining the ecological, heritage and community value of Brockwell Park. The park is overused and underprotected," the PBP said in a statement ahead of the hearing.

The group also led protests in the park.

In a written submission, shaman barrister Richard Harwood KC said in a written submission that over the past few years, the park has been used for large-scale commercial activities, with “substantial” parts fenced and causing damage.

Harwood added: “Due to the weekend weather of a commercial event, the park has effectively become a muddy bath.”

The ruling, known as the Battle at Brockwell Park, highlighted tensions among residents who supported and opposed the incident, brought to South London Park in the summer months.

"I'm waiting for the Park Music Festival season to arrive," wrote the writer Rebecca Tamás.

Another group called Sayyeslambeth believes that the events are a key part of South London’s cultural products. The organization's tagline is: "Fight for the culture, joy and community of Lambes."

In guidance on the case, a member of Sayyeslambeth told London Centric: “Our whole scene and culture will be removed because people complain about the noise when they live in central London.”

The group described the case as "a small and powerful group" and "a battle between young people, renters, workers, small businesses (and) creatives."

Early in the hearing, Moore said: “The planning authorities are going to decide, await the outcome of this challenge, what decisions should be made or should not be made.”

Moore rejected preliminary applications for appeals from Lambes Parliament and Summer Events Ltd., although they could ask the court to allow the decision to be challenged directly.