Extinction Rebellion protesters have blocked one of Covent Garden’s busiest junctions on the first day of the group’s latest wave of protests targeting London. At about midday on Monday, activists from the group chained themselves together to block the roundabout at Long Acre as a van pulled up with a pink table structure. It was quickly assembled and hundreds of other activists streamed to the roundabout. Activists said the 4 metre-high structure, emblazoned with the slogan “Come to the table”, is intended to stay in place for the duration of Extinction Rebellion’s planned fortnight of protest, which the group has said will target the City of London to highlight the role of high finance in the climate crisis. XR said: “As floods, fire and famine break out around the world, it is clear that climate breakdown is here now, and there is no choice left now but to take urgent action. Everyone deserves a seat at the table to have a say in how to tackle the greatest crisis of our times.” Protesters remained in place throughout the day, with officers from the Metropolitan police attempting to impose one-way cordons on the protest that allowed people to leave but prevented any more from joining. Numbers appeared lower than at previous XR protests, with the location seemingly chosen as one that would look crowded even with comparatively few protesters. Activists used lock-on devices to block the roads leading to their occupation, which they said they believed they could keep going for days. At 7pm, police announced through a van-mounted loudspeaker that they had imposed conditions on the protest under section 14 of the Public Order Act. As reggae played from a mobile sound system, officers moved into the crowd and began making arrests. The order, signed by Supt Wayne Matthews, and publicised via social media, said he believed the assembly “may result in serious disruption to the community”. XR protesters targeted for arrest responded by lying supine on the floor, forcing police to use four officers to carry away each protester. By 8.30pm a small nucleus of protesters remained around the table structure. Police later said they had made 52 arrests in relation to the protest. Tristan Strange, 39, from Swindon, was chained to another activist beneath the chassis of a flatbed truck. He said: “By taking these arguably drastic actions, I hope that it makes some of the passersby, or the people who read about it, think about why we are worried enough to do that and it conveys there really is something to worry about.” Laura Amherst, 31, from Brighton, sat on a piece of street furniture topless with XR stickers covering her nipples. She said she was protesting to “raise awareness of how important it is to take the climate crisis seriously”. “People don’t take it seriously and we really need to cut our emissions, we really need to take individual action,” she said. The Met said it was putting into action a policing plan for the expected fortnight of protests. The force’s deputy assistant commissioner, Matt Twist, said: “Like everyone else, Extinction Rebellion have the right to assemble and the right to protest. “However, these rights are qualified and are to be balanced against the rights of others. They do not have the right to cause serious disruption to London’s communities and prevent them going about their lawful business.” On Friday, Twist had said his officers would not be deterred by a recent supreme court ruling, known as the Ziegler ruling, that obstructing the highway could be a legitimate and lawful form of protest. But on the ground, police appeared to be being careful in their approach to protesters, asking them what their intentions were and warning them that they might be committing an offence. The Guardian did not see many arrests taking place. Earlier in the day, thousands of people had gathered in Trafalgar Square for an “opening ceremony”. Launching on the 230th anniversary of the Haitian revolution, XR’s “impossible rebellion” comes after the latest IPCC report suggested that human civilisation may have passed a crucial tipping point in carbon dioxide emissions. Protesters had begun a march from Trafalgar Square and headed up Charing Cross Road, which was apparently a diversion to keep police busy while other activists built the structure on Long Acre. Lautaro Illayux from Colombia spoke at the opening ceremony and marched carrying the Wiphala, the flag of indigenous Latin Americans. He said: “Communities in the global south have been in resistance to this death system since it was first established 500 years ago … There is no way out of this climate emergency without ancestral knowledge.” In a tweet, the Met said: “A group of protesters have blocked the roads around Long Acre junction in Westminster with a structure. Officers are on scene and specialist teams are being deployed. Road closures are in place.”