Environmental protesters have threatened to bring London to a standstill as they attempt to disrupt some of the capital's busiest areas and force the government to declare a climate emergency.
Activists have pledged to block five central locations including Parliament Square in a non-violent act of resistance and rebellion that campaigners say could go on for weeks.
Thousands of people will converge on Marble Arch, Oxford Circus, Waterloo Bridge, Piccadilly Circus, as well as near Parliament, peacefully blocking traffic and creating a "festival" of action including people's assemblies, performances, talks, workshops and food, campaign group Extinction Rebellion said.
The movement, which is demanding the government takes urgent action on climate change and wildlife declines, has received support from actress and activist Dame Emma Thompson and former archbishop of Canterbury Dr Rowan Williams.
Extinction Rebellion co-founder Gail Bradbrook has said that she is “absolutely terrified for her children”.
She told talkRADIO’s Julia Hartley-Brewer: “I have children aged 10 and 13 and I am terrified because I don’t think they have a future.”
Julia accused the activist of scaring her children with “green nonsense”.
Ms Bradbrook added: “The scientists are saying it is time to panic. This is not green nonsense.
This is clear science and people are not facing up to reality. Civilisations collapse that is the historical precedent - that is what happens - when civilisations collapse it gets as far as cannibalism."
Organisers have said that the protesters are 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."
Monday will see people in at least 80 cities in more than 33 countries hold similar demonstrations on the same environmental issues, campaigners said.
Scotland Yard said they have "appropriate policing plans" in place for the demonstrations and that officers will be used from across the force "to support the public order operation during the coming weeks".
Police advised people travelling around London in the coming days to allow extra time for their journey in the event of road closures and general disruption.