Responding for the government, Claire Perry, the energy minister, rejected the idea of a climate emergency - "I don't know what that would entail" - and said she had reservations about the Extinction Rebellion protests.
Dr Steve Melia, who has advised governments on issues including eco-towns and Olympic regeneration, will face charges over an alleged public order offence, it emerged yesterday. Police said then had put a "robust" plan in place, and protesters must leave the square by midnight.
The Metropolitan Police said 1,065 people had been arrested in connection with the demonstrations by 10am on Monday, while 53 of those had been charged.
Those demonstrators not arrested were being allowed to go to a small designated "legal" protest area at nearby Marble Arch.A fter evicting them, police remained at all three sites in force.
While she was glad such arguments were being heard, Perry said: "They have caused disruption for many hundreds and thousands of hard-working Londoners and they have required a heavy policing presence".
"We're trying to work with politicians to make the changes needed in a reasonable time frame to help save our planet", she explained.
Describing the massive state operation he was authorising, Khan said more than 9,000 police officers had been deployed, which had proved "extremely challenging for our over-stretched and under-resourced police".
Siôn Elis Thomas said he hopes the Cardiff protest can help sustain the national movement and believes disruption is a legitimate tactic.
The 16-year-old spoke at a rally in Marble Arch before a week in which she is scheduled to meet Environment Secretary Michael Gove, Labour leader Jeremy Corbyn and Green Party MP Caroline Lucas.
Extinction Rebellion are rallying to demand that the United Kingdom government to declare a climate and ecological emergency and go carbon neutral by 2025.
Members of Extinction Rebellion are suggesting temporarily ending disruptive tactics to focus on political negotiations as they enter the eighth day of campaigning. "But now we realise we have been banned from Parliament Square so we have to negotiate with the police", she adds.
The non-violent protest group is seeking negotiations with the government on its demand to make slowing climate change a top priority.
Overcoming the challenges of rapidly rising sea levels, accelerating Carbon dioxide emissions, loss of biodiversity, collapse of food chains and desertification is bound up with the task of overthrowing the failed capitalist system and its replacement with a socialist society based on rational planning, democratically undertaken on a global scale.