Featured image: A Just Stop Oil activist hoists a banner during the group’s blockade of the M25 motorway, some sections of which carry more than 200,000 vehicles per day. Credit: Leon Neal/Getty

Disruptive and high-profile climate protestors can raise public support for conventional environmental groups, according to an unprecedented study that capitalized on activists’ closure of the United Kingdom’s busiest motorway.

The study is the first to use the public’s real-time response to an actual protest to test the ‘radical flank effect’, which proposes that the subversive fringe of a movement can make mainstream activists seem more reasonable. Many activists think the effect is real. But until now, social scientists have assessed the hypothesis only by using surveys presenting artificial scenarios or by examining past examples, such as the effects on funding of the US civil rights movement.