Met Police chief Cressida Dick has told climate change activists to stop their illegal protests - or go home.
She said patience was running thin among the people and businesses of London as extra police officers were drafted in to cope with the sixth day of protests.
As the number of arrests topped 750, Ms Dick said the protesters should now only stage their actions in the area of Marble Arch - where it should have been legally staged - or go home.
She said: "Stop your unlawful protests. And if you don't want to go to Marble Arch, then go home."
Ms Dick said that in 36 years of policing she had never been involved in a situation where so many people had been arrested during a single incident.
The commissioner added she said she was "very proud" of the work of thousands of officers over the past six days, adding that she was aware that armchair critics would feel things could have been done differently.
Ms Dick said: "We have shown that we are strong, we are determined."
Dozens of officers formed cordons around the group on Waterloo Bridge while protesters reported that arrests were being made at Oxford Circus on Saturday.
As at 4pm on Saturday, police confirmed a total of 750 protesters had been arrested and 28 others have been charged, as the Met said they are aiming to restore "business as usual".
Protesters said that some of those detained had been sent as far away as Brighton and Southampton as the Met runs out of police cells in the capital.
Olympic gold medallist Etienne Stott has said any inconvenience caused by climate change demonstrators in London will be dwarfed by the future ecological emergency as he joined the movement.
The London 2012 canoe slalom champion said civil disobedience by Extinction Rebellion campaigners was "justified" as he put aside university work to protest at Waterloo Bridge on Saturday.
Stott, 39, said he came up to the capital after demonstrating last week in Nottingham and will risk arrest by staying put if police ask him to move on.
He said: "I joined the protests because I don't think there is anything more meaningful that I could be doing in my life right now.
"The climate emergency is just such a serious thing, and for me I'm willing to put in as much time and energy as I can spare and try and use everything I can to try and make the situation better."
Stott said he was currently studying for his final module of a psychology degree he has been working towards for 10 years at the Open University.
He said he was worried about putting aside his assignments, but declared that "the time is now and I've got to be here".
He added: "I feel like it is really really tough to disrupt people's lives like this, but this is really important because I believe the disruption that will come down the line if we do not declare a climate emergency and do not tackle this situation of climate change, it will just dwarf any inconvenience here today."