Hundreds of protesters marched to the Home Office on Saturday demanding deportation proceedings be called off for an environmental activist imprisoned for scaling the Dartford Crossing. Marcus Decker is serving one of the longest sentences ever passed for a non-violent protest in British history after a Just Stop Oil demonstration in October. He is a German citizen with leave to remain in the UK, but faces automatic deportation after serving the two years and seven months sentence. After climbing 60 metres (200ft) up the Queen Elizabeth II Bridge and releasing a Just Stop Oil banner, Decker and fellow activist Morgan Trowland remained on the bridge for almost 40 hours before being removed by police. They were immediately taken into custody and have so far been held for nine months in HMP Chelmsford and HMP Highpoint. Supporters, including from Just Stop Oil, Extinction Rebellion and Insulate Britain, marched from Parliament Square to the Home Office. Speakers at the Don’t Deport Marcus event included Decker, who addressed the crowd by phone from prison, and his partner, Holly Cullen-Davies, who told how she struggled to find a way to tell her children, aged eight and 10, where their stepfather had gone. Threat of deportation on top of imprisonment, she said, had “broken him”. If he was forced to leave Britain, with Brexit and her children’s father in the UK, it would make it very difficult for the family to be together, she said. A petition against his deportation attracted more than 78,000 signatures. Cullen-Davies said the “double punishment” of Decker was “devastating and unjust”. “As a result of their protest, Marcus was sentenced to two years and seven months in prison. But if such a high prison sentence was not bad enough, Marcus, a German citizen, is now being threatened with deportation,” she said. “If deported, he would be separated from his family, his home, community and adopted country. Marcus has already been separated from them for seven months and now he might never come home again.” On 25 May, after eight months in prison and a month after being found guilty of public nuisance, Decker received a letter from the Home Office indicating that he faced automatic deportation to Germany, Just Stop Oil said. Although the group said he was appealing against the prison sentence, his case is not expected to reach the court of appeal until at least January 2024. Indigo Rumbelow, a Just Stop Oil spokesperson, said: “We will be sending a clear message to the home secretary that the cowardly ‘double punishment’ of peaceful people in civil resistance to stop government criminality and protecting the lives of their families will not go unchallenged. “We are demanding that Marcus stays in the UK and is not deported at the end of his sentence so that he can remain with his family, friends and stepchildren.” An Extinction Rebellion spokesperson said: “What has justice come to in this country when citizens raising the climate alarm can face deportation? The real criminals are the government who keep licensing new fossil fuel projects knowing that this will inevitably breach 1.5C of warming and condemn us all to an uninhabitable planet.” A Home Office spokesperson said: “Foreign nationals who commit crimes here in the UK will face the full force of the law, including deportation at the earliest opportunity for those eligible.”