Hackney Council has told Extinction Rebellion to “scale down” its planned festival in London Fields this weekend – but said it supports the three-day protest in principle.

Three days of demos, talks and workshops are set to take place in the borough as campaigners demand immediate action over climate change.

It was set to begin this afternoon with "The Air We Grieve" march from Bethnal Green Tube station up Mare Street to the town hall.

Protesters will then stop traffic outside Dalston Junction station at 9am tomorrow, before a skeleton procession leaves Hackney Downs heading for London Fields in the afternoon.

But town hall chiefs have told them the large-scale event in the park is illegal and unsafe. Chiefs have held talks with the organisers, and say they have agreed to scale it down and focus on "education and sharing ideas".

A statement from mayor Phil Glanville, his deputy Cllr Feryal Demirci and environment chief Cllr Jon Burke states: "The council in no way wants to shape or censor creative protest but we have to be mindful that, despite best intentions, large scale events not properly managed can unfortunately result in people getting injured, being made seriously ill, or exploited by those without regard to public safety.

"The council and police officers have a duty to protect the public and this, above all else, will be our priority this weekend.

"It is our role, where we have the powers, to stop events before they get out of control and put people in danger, or lead to public land or people's properties being damaged, and we can't allow anything which creates a genuine risk of this happening.

"The council and the police have had constructive talks with the organisers and made clear that, though we have no issues with them protesting, their advertised plan for a music stage, festival and overnight camping in London Fields does not have permission and is illegal.

"We welcome that the organisers say they have taken this on board and will scale down the event plan for London Fields to keep it focused on education and sharing ideas, which we broadly support. We hope and believe they will honour this and we continue to have a constructive dialogue."

Hackney Council declared a climate emergency in February and last month passed a motion agreeing to do everything in its power to deliver net zero emissions by 2040, 10 years earlier than the government's target and in line with the Intergovernmental Panel on Climate Change's (IPCC) October report, which stated the world has until then to avoid a devastating increase in global temperatures above 1.5C.

The statement continued: "Hackney has a long and proud history of public protest, a spirit we embrace and something we have all been part of at various times.

"The central message of Extinction Rebellion is one we, and many Hackney residents, support. Whatever our differences on some of the detail, and what is realistically achievable and by when, there is no doubt that we are in a climate emergency and all need to act to address it.

"Extinction Rebellion's previous activities in Hackney, some of which we have attended and spoken at, have so far been well organised, peaceful and constructive, and often creative and inspiring. We hope this weekend follows a similar vein and they deliver on their promise that there will be no drug or alcohol use, no mess left behind, and that each protest will be properly managed and stewarded to keep people safe."

Police have also issued a statement, saying they have informed locals about the demonstrations.