Until Thursday morning, things were going pretty well for the protest group Extinction Rebellion, which has successfully staged a series of effective climate-crisis demonstrations in London since forming in October 2018. Last November, they blockaded five bridges across the Thames, a campaign they stepped up around the climate talks this month. Demonstrators instigated a mass blockade that substantially shut down access to the government district in Westminster, as well as BBC Headquarters and City Airport.

As writer and activist George Monbiot wrote last year, XR aims to foster “a movement devoted to disruptive, nonviolent disobedience in protest against ecological collapse.” More than 1,300 protesters have been arrested in course of this current London campaign, which also included a “mass feed-in” of about 100 breastfeeding mothers outside of Google’s London headquarters.

But then came these chaotic scenes early Thursday morning: Londoners watched as activists glued themselves to, and climbed onto the roofs, of subway trains, forcing transit services to halt on the London Tube’s Jubilee Line and Docklands Light Railway, which shuttle riders to the U.K. capital’s two financial districts. Angry commuters counterattacked, and some demonstrators were set upon violently. There are no reports of medical treatment being needed, but eight arrests of protesters were made.

The Tube protest may have been designed as a wake-up call for a society that the activists believe is speeding towards catastrophe, but the early-morning incident has unfortunately already ended up being something different: a public relations disaster that, against a backdrop of widespread public support among Londoners for Extinction Rebellion’s planet-saving message, has reinforced some of the negative stereotypes about the environmental movement. Right-wing commentators have been quick to damn the protest as “class war” waged by privileged people who have the “luxury of hijacking the underground.”

To understand what went wrong, you need to know a bit about London geography. The stations targeted by activists-Canning Town, Stratford, and Shadwell-are physically very close to the financial district of Canary Wharf. But they are a world removed from it. These stations serve some of the poorest areas not just in London, but in Western Europe. Most commuters shuffling to the train platforms at 7 a.m. (in a country where professionals usually start work after 9) are not wealthy financiers-they’re lower-income workers scraping a living in a notoriously expensive city. Footage of climate protesters with what British people would instantly read as middle-class accents blocking working-class men and women trying to get to their jobs soon after dawn-where they might be sanctioned for lateness-is terrible image-making. It plays into the hands of people who dismiss environmental activism as a hobby for privileged progressives.

That’s a trap that Extinction Rebellion has largely avoided up until now. To a substantial extent, the group developed from the Occupy movement, whose tactics of making protest a permanent public presence they have refined. Elsewhere in Europe, the group has set up a climate camp outside Chancellor Angela Merkel’s office in Berlin, blockaded a shopping mall in Paris, and tried to occupy the canalside outside Amsterdam’s Rijksmuseum and the gardens of the Royal Palace in Brussels.

As with Occupy protests, these encampments have attracted condemnation from those who resent the disruption, but they’ve been peaceful, and the group’s emphasis on striking theatrical tableaus of costumed demonstrators has generated a lot of powerful imagery and sympathetic media coverage. Their message has been consistent: We are in the midst of a climate emergency so serious that it makes complaining about an interrupted commute vanishingly trivial. These protests served their message carefully by staging demonstrations that try to punch upwards-towards government and big finance-rather than down to the ordinary people whose lives are entwined with them.

That’s why the scuffles on London’s public transit were so counterproductive. Official response has been swift, with London Police banning further demonstrations by the group until further notice (a move that Swedish climate activist Greta Thunberg strongly criticized). Mayor Sadiq Khan and rail unions also condemned the protesters, making the obvious point that electric-powered public transit should be considered a climate change solution. Even many members of the protest group itself expressed frustration: The Guardian reported that 72 percent of XR members opposed targeting the Tube, according to an internal poll taken before the protests were carried out.

It’s not hard to see why: These protests not only missed their intended target-the finance companies of Canary Wharf, which are located on private land with ludicrously tight security controls-they ended up creating a false dichotomy, setting up a conflict between the climate movement and public transit users. The optics of the incident end up wrongly implying that working-class London commuters neither care about, nor are affected by climate change.

Extinction Rebellion has also risked playing into the hands of those in the U.K. who dismiss climate change concerns. This is a country with a a bit of bullying, authoritarian streak to its culture; there are those here who really enjoy footage of hippies getting punched, as the ripples of applause for the attacks on protesters on social media illustrate.

As the urgency for climate action grows, Londoners who support Extinction Rebellion’s broader aims can only hope that the group can learn from this experience and adjust their tactics accordingly. The group suggested as much in a statement it released after the incident: “In light of today’s events, Extinction Rebellion will be looking at ways to bring people together rather than create an unnecessary division.”

If that happens, a vital lesson will have been learned. The U.K. capital is a critical player in the global battle for decarbonization. The climate movement needs victories here, and can ill afford to lose the sympathies of its residents.