It is vitally important at this time. It is a matter of life and death - whether you live in Tower Hamlets or Taipei, Melbourne or Mumbai.
Climate protesters have climbed on top of a train in a busy financial district and say they will glue themselves to the roof.
Two Extinction Rebellion demonstrators clambered aboard the carriage of a Docklands Light Railway (DLR) at Canary Wharf station in east London at around 11am on Wednesday.
The pair, a smartly dressed man and woman, unfurled a banner saying "climate emergency", while below them another demonstrator wearing a hi-vis vest appeared to glue his hand to the train window.
The demo comes as authorities disabled Wi-Fi at tube stations in a bid to stop campaigners intent on disrupting Underground services from co-ordinating their efforts.
An Extinction Rebellion (XR) statement said of the DLR stunt: "Our aim is to create moments in time when humanity stops and fully considers the extent of the harm we have done and are doing to life on earth.
"It is vitally important at this time. It is a matter of life and death - whether you live in Tower Hamlets or Taipei, Melbourne or Mumbai."
It comes on the third day of a series of climate change protests which have led to nearly 300 people being arrested in the capital.
A British Transport Police (BTP) spokeswoman said: "In the interests of safety and to prevent and deter serious disruption to the London Underground network, BTP has taken the decision to restrict passenger Wi-Fi connectivity at Tube stations.
"We apologise for any inconvenience this may cause and we would like to assure passengers that this decision is not taken lightly and will be reviewed throughout the day."
Transport for London (TfL) said: "We will restore access as soon as we are able to do so."
XR demonstrations have been taking place at Parliament Square, Waterloo Bridge, Oxford Circus and Marble Arch this week.
The protests have led to road closures, traffic gridlock and serious disruption to public transport and local businesses, with 55 bus routes closed and 500,000 people affected.
The campaign group outlined plans to "non-violently disrupt Tube services to highlight the emergency of ecological collapse" on Wednesday if the Government does not meet its members.
It added: "Participants will peacefully break the law in order to stop the Tube and then will wait to be arrested.
"We sincerely apologise to all those who may suffer as a consequence of this disruption. In any other circumstances we would never dream of disrupting the Tube, but this is an emergency."
Groups of protesters remained in place through the night and into Wednesday morning at several locations, blocking the road at Marble Arch and Oxford Circus.
A woman at Marble Arch, who gave her name as Virginia, said she had come from Oxford to join the protest "to keep the planet in good nick for my grandchildren".
Police have said 290 people had been arrested in connection with the demonstrations, with many of these at Waterloo Bridge.
Five people were arrested on suspicion of criminal damage following disruption outside commercial premises in Lambeth on Monday and have since been released under investigation.
The other 285 people were were arrested on Monday night and throughout Tuesday for Public Order Act offences, obstructing a highway and one for obstructing police as well as two further arrests for criminal damage at a commercial premises on Belvedere Road, Lambeth on Monday.
One arrested protester from Oxford called Ben said he was heading straight back to Marble Arch after being released from custody in the early hours of Wednesday morning.
Scotland Yard said on Wednesday that "contingency plans are in place should custody suites become full".
The Met imposed a 24-hour condition on Waterloo Bridge on Monday evening, telling protesters to continue any demonstrations in the Marble Arch area, but on Tuesday said it extended until Friday.
Another 24-hour condition was imposed in the Oxford Circus area on Tuesday with the force saying a "number of arrests" had been made in the area that evening, but did not give details of how many or on what grounds.
The force added: "There is a need to ensure the right balance is struck between allowing the right to peaceful protest, while disruption to communities is kept to a minimum."
The Met warned that demonstrations are expected to continue "throughout the coming weeks".
Elsewhere on Tuesday, 29 people were arrested after hundreds of activists from the Extinction Rebellion Scotland group occupied Edinburgh's North Bridge, bringing traffic to a standstill.
This article is based on a report from Press Association.