Police have cleared the remaining Extinction Rebellion activists from Waterloo Bridge in London, despite earlier calls on social media for people that were willing to be arrested to “go there and save it”.

The roads around Parliament Square were cleared of protesters earlier on Sunday, with the northbound carriageway of Waterloo Bridge reopened to traffic by the evening. On Sunday night, police continued their operations, moving to remove the last activists, who had glued themselves to the bridge and to each other.

Humanity is at a crossroads, Greta Thunberg tells Extinction Rebellion Read more

Officers had earlier warned people that remaining on the bridge was an “arrestable offence”, and requested that the activists move to Marble Arch, the designated protest area, where hundreds of activists remain.

However, many demonstrators chose to stay at the Waterloo Bridge site, drumming, dancing and singing all along the bridge. At least six campaigners were chained to each other by their hands, with their arms covered with various substances to slow the process of removal by officers. Two men who had glued their hands to the lampposts on Waterloo Bridge were cut free by officers and arrested.

The last protester on the bridge, a 70-year-old woman who did not wish to be named, told the Press Association that said she felt embarrassed to be the last one and was “trying to look dignified”. Having already been arrested at Oxford Circus “chasing after a pink yacht”, she said she would rather be arrested again than walk away, as per the requests of officers.

Asked why it was important for her to join the movement, she said: “I have been a nurse and a childminder most of my life. The world we are leaving for the children and grandchildren is going to be horrendous and we let it happen. It happened on our watch. So we have to stand up and fight or lie down and fight.”

Facebook Twitter Pinterest Police remove a Extinction Rebellion protester from Waterloo Bridge on Sunday evening. Photograph: Penelope Barritt/REX/Shutterstock

The Metropolitan police has requested about 200 extra officers to help deal with the protests, in which 963 people have been arrested and 42 people, aged from 19 to 77, charged.

Extinction Rebellion have said there will be a “people’s assembly” at Marble Arch on Monday afternoon to decide what will happen in the coming week, with the movement appearing split on what next steps to take in their campaign of non-violent civil disobedience.

Greta Thunberg, the teenage climate campaigner, made a speech in solidarity with the protesters in Marble Arch. The Swedish student took aim at the “politicians and people in power” who had long been able to satisfy demands for action with “beautiful words and promises”, and declared that governments would no longer be able ignore the impending climate and ecological crisis.

“I come from Sweden and back there it’s almost the same problem as here, as everywhere, that nothing is being done to stop an ecological crisis despite all the beautiful words and promises,” she said, after being greeted with loud cheers.

Play Video 1:59 ‘We will never stop fighting’: Greta Thunberg addresses London climate protests – video

“We are now facing an existential crisis, the climate crisis and ecological crisis which have never been treated as crises before. They have been ignored for decades and for way too long the politicians and the people in power have gotten away with not doing anything. We will make sure that politicians will not get away with it for any longer.”

Thunberg, who has been credited with inspiring a worldwide movement to reduce carbon emissions, said humanity was sitting at a crossroads. She told those gathered at Marble Arch that they had chosen which ecological path they wanted to take. She emphasised that they were now waiting for the rest of the world to follow their example.

“We are the ones making a difference, we the people in this Extinction Rebellion and the children’s school strike for the climate,” she said. “It shouldn’t be like that, but since no one else is doing anything, we will have to do so.

“We will never stop fighting for this planet, for ourselves, our futures and for the futures of our children and grandchildren.” Later, Massive Attack played a concert for the crowds.

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Thunberg will meet MPs including the Green party MP Caroline Lucas, the Labour leader, Jeremy Corbyn, and the environment secretary, Michael Gove, next week. She has been touring Europe throughout her Easter holidays, imploring leaders to take radical action before it is too late.

Last week, she poured scorn on EU leaders for holding three emergency summits on Brexit and none on the threat posed by climate change, suggesting that it evidenced politicians’ disinterest in tackling climate change. Her speech was given a standing ovation.

Thousands of Extinction Rebellion campaigners had blocked four areas in central London on Monday, but on Saturday police regained control of Oxford Circus.