Furious commuters at a crowded Canning Town station lobbed drinks at one protester before he was yanked from the train to the platform floor, much to the apparent delight of the cheering horde.
Video shared on social media showed protesters holding a sign which read “Business as usual = death”, while the activist pulled to the floor appeared to kick out at the commuter who pulled him down.
British Transport Police confirmed eight people had been arrested on suspicion of obstructing the railway on Thursday morning and also urged commuters not to “take matters into their own hands”.
A member of Transport for London (TfL) staff appeared to intervene to stop people from attacking the male XR activist further by holding them back.
One man yelled “I need to get to work, I have to feed my kids”, while others shouted insults at activists.
It was one of a number of stunts across the capital, although service across the network has since returned to normal.
British Transport Police also said it was investigating the response from commuters and acting chief constable Sean O’Callaghan added: ‘It is important that commuters and other rail users allow the police, who are specially trained, to manage these incidents.”
XR spokesman Howard Rees, 39, told the PA news agency: “Was it the right thing to do? I am not sure.
“I think we will have to have a period of reflection. It is too early to say.
“I think we need to take stock of it.”
Mr Rees, a PR worker from London, said the intention was not to “inconvenience hard-working people”, and said he did not think the apparently unsympathetic mood on the platform was indicative of a decrease in public support despite many posts on the XR London Facebook page expressing concerns that the stunt was counterproductive and should not have gone ahead.
He said: “It is not our intention to target individuals or inconvenience hard-working people.
“We’re in a life or death situation right now.
“The only thing the Government is interested in is money, so that’s why the transport system was targeted.
“If you’re causing disruption but people are impacted, it is nothing compared with the disruption that is coming down the line, let me tell you.
“It (the footage) was really horrifying, I’m deeply distressed by it.
“I’m concerned for everybody who was caught up in it.
“I really hope he (the protester) is all right. My understanding is he is in custody.
“I don’t think it (the footage) is reflective (of the public support).
“The passive support at the beginning of last week is not what we need.
“What we need is active support, people who are willing to get arrested, and that doesn’t have to come from a majority.”
He said the protests were carried out by activists “affiliated” to Extinction Rebellion, meaning anyone with the same ideals could act under the XR banner.
The action is the latest in a series from the anti-climate change group, who have been banned from protesting in London.
A legal bid to overturn the order is expected to reach the High Court on Thursday afternoon.
A single group of Extinction Rebellion protesters were at Gatwick Airport, handing out flyers to passengers passing through the terminal, but made no attempt to disrupt travel.
Steve McDonald, 63, said that the “leafleting exercise”, conducted by around 20 activists, was a “call to arms”.
“People came alone because they want to do it, they passionately want to do it,” he said.
He said that the decision to protest on the London Tube had not been welcomed by all Extinction Rebellion members.
“XR had a problem this morning,” he added. “Obviously it went wrong, that was never our intention but I don’t condemn those people.”
Since last week, protesters have targeted London City Airport, shut down areas around Parliament and the Bank of England, and blockaded Google’s HQ, with more than 1,600 people arrested.
The local MP reacted angrily to Thursday’s travel disruption.
Jim Fitzpatrick, Labour MP for Poplar and Limehouse, asked: “So what point is Extinction Rebellion making shutting down east London’s public transport system, preventing ordinary people from getting to work, school, hospital?”
But XR co-founder Clare Farrell defended the Tube action and said: “The public, I don’t think, realise quite how serious this situation is.”
London Mayor Sadiq Khan condemned Thursday morning’s protest, calling it “an unfair burden on our already overstretched police officers”.