Hundreds of clinical psychiatrists and psychologists have warned that the police and crime bill reaching its final stages in parliament “will have a profound negative impact on young people’s mental health”. “We cannot think of better measures to disempower and socially isolate young people,” they say in an open letter signed by more than 350 academics and clinicians and published online. The intervention comes as the police, crime, sentencing and courts bill reaches the final stages of its journey into law. It has been widely opposed by human rights activists, racial justice groups, former home secretaries and parliament’s joint committee on human rights, which called the proposals “oppressive and wrong”. Among the anti-protest measures in the bill are new powers for police to ban marches and demonstrations deemed “seriously disruptive”, including being too noisy; sentences of up to 51 weeks for protesters who attach themselves, or “lock on” to, another person or to an object; and sentences of up to 10 years for anyone found guilty of the “desecration” of a statue or memorial. “One result of this legislation, if passed, will be that young people face a choice between being intimidated into inaction and isolation, or possibly criminalised if they choose to act,” the letter says. “Some may deliberately choose to escalate their actions to be more disruptive and possibly violent, given the severe consequences for even minor nonviolent activity.” Signatories include Susie Orbach, psychoanalyst and author of Fat Is a Feminist Issue, Eric Taylor, the emeritus professor of child and adolescent psychiatry at King’s College London, and Mike Wang, the chair of the Association of Clinical Psychologists, who signed on behalf of his entire organisation. Orbach said young people, full of the “great hope and ennui” of adolescence, were keen to make a difference to the world. “Imagine then a bill that robs you and your friends of initiative and agency,” she said. ‘“We bring children up to act and then the government says no. This bill sews confusion. It attempts to disable engagement. It will depoliticise youth, which is maybe what is wanted, but what a tragedy personally and collectively.” The letter was drafted by Lynne Jones, a consultant child and adolescent psychiatrist, who was awarded an OBE for her work with children in conflict zones in central Europe in the late 90s. Jones said she was inspired by an Australian environmental activist, Marco Bellemo, who called on professionals to oppose restrictions on activism. She said of the bill: “It is terrifying because it is undermining one of the pillars of our democracy, and it is also attacking the young people who most need our support. “Priti Patel has made no bones that she’s targeting eco-protesters, that means she’s targeting young people.” The Guardian has contacted the Home Office for comment.