Three Sheffield tree campaigners are due in court today for the start of a three day fight against the city council.
The authority hopes to get an injunction against the campaigners, who it says have been protesting unlawfully against felling across the city.
The council says protests within safety barriers put up around trees are putting people in danger and constitute trespass.
But campaigners say they have every right to peacefully oppose the felling of healthy trees as part of the Streets Ahead programme, carried out by contractor Amey.
Among those in court in Leeds this morning is Alison Teal, a Green Party councillor for the Nether Edge and Sharrow ward.
She is joined by Dave Dillner and Calvin Payne.
Five others, Alice Fairhall, Robin Ridley, Graham Turnbull, Paul Brooke and Simon Crump, were due to appear but have instead signed undertakings agreeing not to take part in any further 'direct action' against felling - including standing within safety barriers, stopping Amey workers trying to put them up, or encouraging anyone else to do so, even via social media.
The council is also seeking an injunction against an unnamed person.
The hearing is due to last until Thursday.
If the campaigners are served with injunctions and break them they will be in contempt of court, and could face fines or even prison.