A doctor could be struck off the medical register after taking part in a Just Stop Oil demonstration.
Dr Sarah Benn, a GP from Birmingham, was arrested after taking part in a demonstration at the Kingsbury oil terminal in Warwickshire in 2022.
Dr Benn held a sign saying "no new oil" and was subsequently found to be in breach of a civil injunction and was imprisoned for 31 days, Just Stop Oil said.
The Medical Practitioners Tribunal Service (MPTS) started the hearing to decide if the 57-year-old can maintain her licence to practise medicine on Monday, with the tribunal expected to last until 24 April.
Just Stop Oil described the demonstration in Kingsbury as a "peaceful demonstration demanding the government to bring an end to new fossil fuel projects".
On its listing of the hearing, the Medical Practitioners Tribunal Service says: "The tribunal will inquire into the allegation that on 26 April 2022, 4 May 2022 and 14 September 2022, Dr Benn engaged in peaceful protests within a prohibited buffer zone at Kingsbury Oil Terminal in breach of an interim injunction granted on 14 April 2022."
According to Just Stop Oil, Dr Benn informed the General Medical Council and her employer after each arrest and she argues that her actions are consistent with medical ethics, which prioritise patient and public safety above all.
Speaking before the hearing, Dr Benn said: "As a doctor, my fundamental duty is to protect health and life. The climate crisis is the most significant existential threat to global health we have ever faced."
Dr Benn said she did not take the protests and disruptions she had participated in lightly but said people "must be clear about the magnitude of the crisis we face".
"I will continue carrying out what I believe is my responsibility as long as the government refuses to commit to stopping oil and gas."