More than 100 people were arrested on Wednesday in the climate protests that have caused major disruption in central London, Scotland Yard said, taking the total number of arrests to almost 400.

Activists stepped up the demonstrations on their third day, targeting the capital’s rail network and the home of the Labour leader, Jeremy Corbyn.

Traders in the West End warned that the protests, which have seen protesters block four London landmarks for the past three days, had already cost them tens of millions of pounds.

More than 300 arrested at Extinction Rebellion protests in London Read more

The first estimate of the financial impact of the so-called climate rebellion came as activists targeted London’s rail network. Just after 11am, three people glued themselves to a train at Canary Wharf station, causing delays on the Docklands Light Railway.

A few hours later, four protesters glued their hands together and chained themselves to a fence outside Corbyn’s house, saying he was “the best hope this country has got” to meet the challenges of the climate crisis, adding that they were there to “support him” to go further.

Thousands of people, including parents and young children, pensioners, scientists and environmentalists, have taken part in Extinction Rebellion protests.

On Wednesday afternoon, the four sites that protesters had occupied in London since Monday – Marble Arch, Waterloo Bridge, Parliament Square and Oxford Circus – remained under their control, causing ongoing delays and diversions in the surrounding areas.

Q&A What is Extinction Rebellion? Show Hide Extinction Rebellion is a protest group that uses non-violent civil disobedience to campaign on environmental issues. Launched in October 2018, with an assembly at Parliament Square to announce a 'declaration of rebellion' against the UK Government, the group has staged regular demonstrations against current environmental policies. More than 1,000 activists were arrested in April 2019 after protesters occupied four sites across London, as well as blocking roads, disrupting a railway line and conducting a protest at Heathrow. Other demonstrations have included a semi-naked protest inside the House of Commons and blockading streets in London, Cardiff, Leeds, Bristol and Glasgow. The group says climate breakdown threatens all life on Earth, and so it is rebelling against politicians who “have failed us”, to provoke radical change that will stave off a climate emergency. The movement has become global with groups set up in countries include the US, Spain, Australia, South Africa and India. Martin Belam Photograph: Anadolu Agency/Anadolu

The Metropolitan police has designated Marble Arch as a legitimate protest site. By early evening, large numbers of police officers had turned out in force at the other three sites announcing they were imposing a section 14 order requiring protesters to leave.

Several hundred officers appeared in Parliament Square, removed sparsely manned roadblocks and took down gazebos, apparently retaking the space without difficulty. However, there were reports that activists had managed to hold the space after the arrival of a samba band, while others tried to set up new barriers around the square.

In Oxford Circus, police circulated among the crowd, who had been dancing all day to music from a stage mounted on a pink boat, serving notice on each.

Police made a concerted attempt to clear Waterloo Bridge by walking among the crowd and serving section 14 notices on all the people assembled there, telling them they had the right to either to go home or continue their protest in Marble Arch. Anyone who refused to comply was arrested.

Play Video 0:39 Climate protesters climb on top of train at Canary Wharf – video

By 9pm the Guardian had witnessed police carry away at least a dozen protesters, while many others left of their own accord. People who had already been served notice were arrested straight away if they did not leave after a few minutes.

There was pandemonium at times as police officers walked through the crowd, picking individuals apparently at random. A large number of police officers arrived as reinforcements at about 8.30pm.

However, numbers of protesters remained strong and cheers erupted each time an arrest was made. By 9.15pm they were led in a call and response song and chants of “whose police? our police. Whose hearts? Our hearts. Whose souls? Our souls.”

On Tuesday, organisers had warned that they were planning to disrupt London’s rail and tube network, and just after 11am three activists glued themselves to a DLR train at Canary Wharf, unfurling a banner reading, “Climate emergency – act now.” Two people then glued themselves to the top of the train. Another man, who gave his name as Mark, glued himself to the side of the train. The protesters were finally removed from the roof by police at 12.40pm.

Cathy Eastburn, 51, was one of those taking part in the transport disruption. She said she decided to make a stand for her teenage daughters. “I don’t want to be here today and I’m really sorry for the disruption, but I feel I have been forced to do this,” she said. “I have two daughters and I can’t sit by while their future is threatened … The government is doing nothing – we have to force them to act.”

Gail Bradbrook, one of the founders of Extinction Rebellion, who was at the scene, said: “This [Canary Wharf] is the heart of the system that is bringing us to our knees causing huge disruption and chaos around the world … so we want people to pause and reflect.”

A few hours later another group of activists glued themselves together, then chained themselves to the fence of Corbyn’s house. The Labour leader left his home a few hours later saying he never gave interviews, or arranged meetings, outside his house. The activists left shortly after, saying Labour had offered to meet Extinction Rebellion next week.

David Lambert, 60, was one of those taking part. “We are here because we are supporters of Jeremy Corbyn and he is the best hope this country has got to get us out of this,” he said. “But we need system change and a transformation of our consumer economy and we know he is a person who has the authority and power to deliver that.”

The events in London are part of an international “climate rebellion” organised by the UK-based Extinction Rebellion. Protests had taken place or were planned in 80 cities across 33 countries, from India to Australia, and around Europe and the US. In The Hague , activists occupied the international criminal court building on Tuesday.

Play Video 4:05 'If this is what it takes': London​ reacts to the Extinction Rebellion ​'shutdown' – video

Twenty-nine arrests were made in Edinburgh on Tuesday night after police cleared remaining activists who who staged a sit-in on North Bridge. By 6am on Wednesday, they had all had been released and charged with breach of the peace, to appear in court at a later date.

In London, Extinction Rebellion protesters, activists and legal observers said some of those arrested were being taken to police stations outside of London, lending credence to persistent rumours that the Metropolitan police’s holding cells were reaching capacity. Several people reported cases of people being taken to Luton, Brighton and Essex. The Met would not confirm or deny the claim.

On Wednesday, Jace Tyrrell, the chief executive of New West End Company which represents Oxford Street and central London retailers, told Sky News the protests were hitting business hard.

“We have seen a 25% drop in spend – it was £12m yesterday and obviously we have had disruption today. The impact is customers thinking they are not going to come up over the bank holiday so this could go into the hundreds of millions of pounds if we do not grip this.”