We cannot go on with subsidising fossil fuels, we cannot go on with our road building programme, we cannot go on even with our nuclear programmes.
Extinction Rebellion activists began protesting at a number of east London stations early on Thursday morning - the penultimate day of two weeks of its "Autumn uprising".
Assistant Chief Constable Sean O'Callaghan said BTP the force had "engaged" with XR members to prevent the planned "disruptive and potentially criminal" action on the transport network.
British Transport Police said just after 7am: "At this time we have three separate incidents involving Extinction Rebellion protest action at Stratford, Canning Town, and Shadwell. Arrests have already been made and officers are working quickly to resume services."
Commuters were seen dragging one of the protesters from the roof of the train at Canning Town. In a clip posted on Twitter, one of the activists was pulled from the train by his foot, and ended up on the ground surrounded by train users who shouted at him.
A member of TfL staff appeared to stop people from attacking the male activist further by intervening and holding them back.
The latest action comes as XR's bid to defy the blanket protest ban on its protests across the whole of London will come before the High Court on Thursday.
Those bringing the court action on behalf of the group, including Caroline Lucas MP and Guardian columnist and activist George Monbiot, are seeking to overturn the order imposed by the Met.
They argue that the order is an "unprecedented and disproportionate curtailment" of the right to free speech and free assembly which risks criminalising protest about the climate and ecological emergency in the capital, and want the High Court to rule that the decision to impose the ban is unlawful.
Lawyers representing the climate protesters will argue in a preliminary session that a full hearing of the case should happen 'as a matter of urgency'. They will argue that the section 14 order imposed by the Met effectively banning all XR protests in London is unlawful.
A Green Party co-leader was among the latest people to be arrested as Extinction Rebellion protesters continued to defy a police ban yesterday.
Jonathan Bartley was also arrested after joining climate change protesters on Whitehall. Protesting on his birthday, Mr Bartley said: "We cannot go on with HS2 destroying acres and acres of countryside.
"We cannot go on with subsidising fossil fuels, we cannot go on with our road building programme, we cannot go on even with our nuclear programmes."
After his arrest, a Green Party spokesman said: "Climate chaos will end ecosystems and collapse our society. We have just 10 years to reduce our C02 emissions to safer levels and climate protesters are drawing attention to that.
"We all have a right to peaceful protest and we will continue to act to protect that right and draw attention to instances where democracy is threatened."
George Monbiot, a columnist at The Guardian and climate change activist, joined more than 500 Extinction Rebellion activists in Trafalgar Square.
Mr Monbiot, who had written a column in Wednesday's newspaper vowing to get arrested, was detained by police after lying down in the road at Whitehall.
During his arrest, Mr Monbiot, 56, said: "I'm here because this is the right thing to do. We have to stand up, we have to make a stand against the destruction of our life support systems."
Hundreds of activists in Trafalgar Square put black tape over their mouths, to symbolise the silencing of their protests by police.
Councillor Andree Frieze, Green Party candidate for Richmond South, who took part, said: "This symbolises the way our voices are being shut down, our voices are not being listened to."
Elsewhere, Extinction Rebellion mothers and babies blockaded Google HQ in London over what they say are donations to climate change deniers. Around 100 mothers and babies blockaded one side of the building by staging a mass feed-in, the group said.
In 10 days of protests to call for urgent action on climate change and wildlife losses, Extinction Rebellion activists have shut down the areas around Parliament and the Bank of England, and targeted City Airport and government departments.
The Met Police used section 14 of the Public Order Act initially to restrict the Extinction Rebellion protest action to Trafalgar Square, but following "continued breaches" of the order officers moved in to clear the area. Any assembly of more than two people linked to the XR Autumn Uprising action is now illegal in London.
By Wednesday morning 1,642 protesters had been arrested, and 133 charged. XR's stated tactics are to overwhelm the capacity in police custody, including by refusing bail after being arrested.
Before Wednesday's action Mr Taylor warned activists that they would be arrested if they assembled in Trafalgar Square.
On Thursday XR activists plan to target the Tube network, which the senior officer called "unacceptable".
He said: "That will cause huge disruption for London and we consider that wholly unacceptable, and obviously will be policing that with our partners at British Transport Police."
A Government spokesman said: "The UK is already taking world-leading action to combat climate change as the first major economy to legislate to end our contribution to global warming entirely by 2050.
"While we share people's concerns about global warming, and respect the right to peaceful protest, it should not disrupt people's day-to-day lives."
The Met's Deputy Assistant Commissioner, Laurence Taylor, who is leading the policing of the demonstrations, has insisted the order is legal.
Meanwhile, Boris Johnson, the prime minister, announced during the protests that he will chair a new Cabinet committee on climate change to drive environmental action across government.
It will bring together ministers responsible for domestic and international climate change and provide a forum to hold departments to account for their actions to tackle the problem.
It is hoped it will drive further action across Government to cut emissions, protect the environment and improve air quality.
The statement comes after plans to end the UK's contribution to climate change by cutting emissions to net-zero by 2050 were enshrined in law in the summer.
The committee will play a key role in co-ordinating the move to net-zero, and will oversee the UK's preparations to host a major UN climate summit in November 2020, Number 10 said.
Mr Johnson said: "I'm announcing today that I will personally chair a new cross-government Committee on Climate Change, bringing together my ministers to galvanise action to tackle the great environmental challenges we face."
Rebecca Long Bailey, the Labour MP and shadow secretary of state for Business, Energy and Industrial Strategy, said: “There is possibly no one more ill-suited to this role than a prime minister with a history of climate denial, from a Tory government that has dismantled the UK’s solar and onshore wind industries, overseen a collapse in household energy savings measures and stalled the UK's progress cutting emissions.
In power Labour will kick start a Green Industrial Revolution, tackling the climate crisis and transforming lives. We are the only party with credible and detailed plans to do so.”
But Craig Bennett, Friends of the Earth chief executive, said: “With the planet facing a climate emergency, we need urgent action not just warm words.
“The Prime Minister’s pledge to make the UK a global leader on the climate crisis will only be realised if slashing climate-wrecking emissions is at the very heart of every government policy.
“This means scrapping plans for a third runway at Heathrow, halting the multi-billion pound road-building programme and abandoning support for fossil fuel development at home and abroad.
“The solutions for building a carbon-free future already exist – but has Boris Johnson got the political will to make it happen?”
Emily Beament, Margaret Davis and Laura Parnaby are reporters with PA. Image: Dominic Lipinski/PA Wire.