Norwich's City Hall has been daubed with pink paint as part of a political protest.
In co-ordination with nationwide action, members of Burning Pink threw pink paint at the facades of Norwich City Council and Norfolk County Council buildings in protest at their "treasonous inaction on the climate and ecological emergency".
Officials have slammed a "totally unacceptable act of vandalism" in which the bronze doors were targeted at Norwich City Hall.
A spokesperson for Norwich City Council said the police are now investigating the matter.
They added: “Vandalism and destruction can never be justified. Such acts immediately undermine any coherent argument being made.
“The bronze doors of City Hall are a work of art which depict the history, trade and industry of the city. The damage to them and the surrounding stonework of the Grade II* listed building is extensive.
“We will need to bring in specialists to advise us on how to proceed with restoration work. There will inevitably be a considerable cost to this.”
Burning Pink Norwich, which is described as an anti-political party, has claimed responsibility for the act on its social media page.
A post by the group said: "Now is the time to take action. We have one last chance to fight for the future of civilisation as we know it.
"Our governments are complicit in the murder of millions of humans, and billions of non-human animals across the globe. Time is rapidly running out.
"Their refusal to properly acknowledge and lack of action to halt the irreversible damage and destruction of the one planet we call home is already causing famine in the East and before you know it they'll have you and I fighting over rations of oats."
The group said two people were arrested in Norwich after the protest.
Further social media posts by Burning Pink show the act was replicated across the country including Ipswich Borough Council and Brighton Town Hall.
On January 18, Burning Pink demanded that local councils honour their climate emergency declaration to act on the ecological collapse and social breakdown, or they would begin a nationwide campaign of nonviolent civil disobedience.
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