Last week, five supporters of the Just Stop Oil climate campaign who conspired to cause gridlock on London’s orbital motorway were sentenced to lengthy jail terms by a judge who told them they had ‘crossed the line from concerned campaigner to fanatic’. Columnist and campaigner George Monbiot tells Ian Sample why the sentences are so significant, how they fit into a crackdown on protest in the UK in recent years, and what impact they could have on future climate activism in the UK. Help support our independent journalism at theguardian.com/sciencepod