Police have said they have a "robust" plan in place ahead of a proposed climate change protest in Parliament Square.
The demonstration on Tuesday - which coincides with the first day Parliament is sitting following the Easter recess - is the latest action by Extinction Rebellion (XR) protesters in the capital.
Protesters have been told to remain in Marble Arch but organisers are planning to march to Parliament Square for 10am.
The suggestion is they plan to block MPs from going back into Parliament.
Police orders didn't stop some protesters lying down at the Natural History Museum on Monday afternoon.
Wearing red face paint, veils and robes, some remained to give a performance to classical music on the steps under the famous blue whale skeleton.
Marble Arch, the only location where protesters are allowed to remain, has become a hub of activity as Extinction Rebellion demand their voice is heard.
One of the speakers, Savannah Lovelock, 19, from Extinction Rebellion Youth, told a crowd of around 1,000 people at Marble Arch on Monday she was willing to quit university for the cause.
"I'm dropping out of university for this because there is nothing is more important than this," she said.
"You are taking away my future, you're taking away our dreams - I want you to look me in the eye."
Hundreds of people gathered around the arch over the bank holiday weekend, with musical performances coming from electronic dance group Massive Attack on Sunday evening.
The Metropolitan Police confirmed more than 1,000 people have been arrested since the start of the protests. 53 of those taken into custody have been charged.
Olympic gold medallist Etienne Stott was one of the activists arrested as police moved to clear Waterloo Bridge on Sunday evening. Earlier in the day, outspoken conservationist Chris Packham joined protesters - standing on a bus shelter to express his message.
The London 2012 canoe slalom champion was carried from the bridge by four officers at around 8.30pm as he shouted about the “ecological crisis”
A spokesman said there would be no escalation of activity on Easter Monday, but warned that the disruption could get “much worse” if politicians are not open to their negotiation requests.
Activists will meet to “vision what’s going to happen in the coming week”, an Extinction Rebellion member said, as she introduced Swedish activist Greta Thunberg to the stage.
The 16-year-old was met with cheers as she walked on stage and told a crowd of hundreds that humanity was at a crossroads.
Earlier on Sunday, in what the group later said was an internal memo intended to garner feedback from members, Farhana Yamin, the group’s political circle co-ordinator, said they would shift tactics to “focus on political demands”.
She added: “Being able to ‘pause’ a rebellion shows that we are organised and a long-term political force to be reckoned with.”
The proposal suggests negotiating with London Mayor Sadiq Khan and the Metropolitan Police to agree they be allowed to continue their protests at one site.
Members would commit to not disrupting other areas in exchange for Mr Khan speeding up the implementation of the Declaration of Climate and Ecological Emergency, and considering setting up a London Citizens’ Assembly.
They will also set up a political taskforce to take forward public negotiations with the Government, warning that they are prepared to scale up action depending on how much progress is made.
Neither the Met nor the Mayor’s Office would say whether they were considering the proposals.
Boris Johnson, Mr Khan’s predecessor as mayor, wrote in the Daily Telegraph that he was “not in favour of paralysing public transport in the greatest city on Earth” and said the UK was a “world leader in reducing the greenhouse gases that are associated with climate change”.
He wrote: “I am not saying for one second that the climate change activists are wrong in their concerns for the planet – and of course there is much more that can be done.
“But the UK is by no means the prime culprit, and may I respectfully suggest to the Extinction Rebellion crew that next Earth Day they look at China, where CO2 output has not been falling, but rising vertiginously.
“Surely this is the time for the protesters to take their pink boat to Tiananmen Square, and lecture them in the way they have been lecturing us.”