London’s protests are part of a wider campaign which will see people in at least 80 cities in more than 33 countriesCredit:Leon Neal/Getty Images Glass has been shattered at Shell’s headquarters near Waterloo stationCredit:Jonathan Brady/PA Want the best of The Telegraph direct to your email and WhatsApp? Sign up to our free twice-daily Front Page newsletter and new audio briefings. By midnight, there had been a total of 52 arrests, the majority for public order offences and obstruction of the highway, Scotland Yard said.The XR group are targeting Marble Arch, Oxford Circus, Waterloo Bridge, and Parliament Square with plans to block the routes “for as long as it takes”, making it inevitable that they will be arrested for obstruction.Waterloo Bridge was blocked in both directions this morning as dozens of activists gathered. A tweet on the campaign group’s Twitter page read: “We have taken Waterloo bridge!” The group warned the protests could take place in the middle of roads for weeks, meaning protesters may face arrest for obstructionCredit:Henry Nicholls/Reuters Skateboarders replaced cars and lorries on Waterloo Bridge as the Thames crossing was closed to traffic and decorated with pot plants and trees.Organisers say thousands of people will also converge on Marble Arch, Oxford Circus, Piccadilly Circus and Parliament Square in non-violent action which could last for weeks.In Oxford Street, a huge pink boat was unveiled in the middle of the road, which was also shut as part of the protests. Extinction Rebellion said protests in London could last a couple of weeksCredit:Henry Nicholls/Reuters Activists blocked Oxford Street and other busy parts of London to highlight the threat of global warmingCredit:Amer Ghazzal/REX The Metropolitan Police said officers would be used from across the service to provide a “proportionate” response to the protests, which balanced the right to a peaceful protest while ensuring disruption to communities was kept to a minimum.A spokesman urged travellers to allow extra journey time as road closures and disruptions to the travel network were expected.A Transport for London spokesman said: “The safety of our customers and staff is our number one priority and we’re working closely with the police to manage the impact on London’s transport network. The movement has received support from actress and activist Dame Emma Thompson and former Archbishop of Canterbury Dr Rowan WilliamsCredit:Jeff Gilbert Demonstrators arrived at London’s Hyde Park on Sunday, some having journeyed to the city on foot in recent weeks from various parts of the UK for what is described as an “International Rebellion”.Today will see people in at least 80 cities in more than 33 countries hold similar demonstrations on the same environmental issues, campaigners said.While organisers encouraged people to set up camp in Hyde Park overnight into Monday, they were warned they could be breaking the law by doing so under Royal Parks legislation.A spokeswoman for The Royal Parks said Extinction Rebellion had not asked for permission to begin the protest in the park and that camping is not allowed.But police said no arrests were made overnight after earlier explaining their operational response to camping “would be dependent on what if any other issues might be ongoing at the time”. “We would encourage people to check their journeys before they travel.”Monday’s demonstration comes as part of attempts to force the Government to declare a climate emergency. Earlier this month, several Extinction Rebellion activists stripped semi-naked in the House of Commons during a Brexit debate.The movement has received support from actress and activist Dame Emma Thompson and former archbishop of Canterbury Dr Rowan Williams. Organisers said: “The International Rebellion begins and Extinction Rebellion will be bringing London to a standstill for up to two weeks.”They will be blocking five of the city’s busiest and most iconic locations in a non-violent, peaceful act of rebellion where they invite people to join them for several days of creative, artist-led resistance.”Protester Olivia Evershed, 23, said: “I hope that it’s really going to bring awareness about the emergency crisis that we are in, and encourage the Government to act. A boat is placed in the centre of the traffic junction as Environmental campaigners block Oxford CircusCredit:Leon Neal/Getty Images Speaking at a meditation on the eve of the protests Dr Williams said humans had declared war on nature.He said: “We are here tonight to declare that we do not wish to be at war. We wish to make peace with ourselves by making peace with our neighbour Earth and with our God.”Thompson has previously said of the demonstrations: “It is time to stand up and save our home.” The movement demands the Government takes urgent action on climate change and wildlife declinesCredit:Henry Nicholls/Reuters Marble Arch was also blocked, while demonstrators caused further disruption as they made their way from Hyde Park Corner to Piccadilly Circus.On Monday evening the Metropolitan Police imposed conditions on the protesters, restricting them to gathering in the area around Marble Arch.At Parliament Square, people unfurled banners, held up placards and waved flags as speakers took to the stage.XR, whose prime goal is to reduce carbon emissions to zero by 2025, claims between 3,000 and 6,000 supporters could take part in the protests. Last November, they blocked bridges across London to bring chaos to the capital.Sophie Cowen, an Oxford French graduate who joined the group in November and now acts as media co-ordinator, pledged non-violent civil disobedience: “It’s 100 per cent about obstructing traffic and making sure we bring it to a standstill. People are willing to be arrested.” “They can change a few of the laws along with the Paris agreement so that we can really work towards achieving a practical target.”We’ve got 12 years to act before there is irreversible damage to the environment and we start to see catastrophic changes. If we don’t do anything to change this, our children will die.”Laura Jordan, 52, said: “This protest stands a good chance of working because we have a vast amount of ordinary people all saying the same thing.”We need to change the way we do everything, the way we use fossil fuels. But this starts with the Government.” Protesters outside the Shell headquarters in LondonCredit:Andy Rain/REX More than 50 people were arrested as climate protesters staged Extinction Rebellion (XR) demonstrations across the capital on Monday.Police were called to the Shell Centre, the London headquarters of the major oil firm near Waterloo station, to reports of a disturbance after the building’s revolving doors were shattered and graffiti was daubed on to the building. Messages such as “Shell kills” were sprayed on to the property, while a female climate change activist glued herself to the door of the building.A Shell spokeswoman said: “We respect the right of everyone to express their point of view, we only ask that they do so with their safety and the safety of others in mind.”The building was one of five locations targeted by protesters across the capital. Radical environmental protesters blocked major London roads in an attempt to bring the capital to a standstill.