A crowd of angry London commuters have dragged two Extinction Rebellion protesters off a train as the pair attempted a climate action demonstration during peak hour.

Key points: Eight protesters were arrested after three peak-hour demonstrations at London train stations

Eight protesters were arrested after three peak-hour demonstrations at London train stations Police are investigating the outbreak of violence at one of the protests, telling commuters to let officers handle activists

Police are investigating the outbreak of violence at one of the protests, telling commuters to let officers handle activists An independent journalist said he was beaten by 20 Londoners while he was filming the protest

Footage shared on social media shows two activists standing on top of the Tube in front of a shouting crowd at Canning Town, in east London.

UK newspaper The Telegraph reported one of the activists was chased along the train roof before also being pulled down to the platform.

A video shared on Twitter shows a transport worker shielding a protester as a group of shouting people closed in around him.

Elliot Laughlin, an independent journalist, told the BBC the crowd attacked him when they saw him filming the demonstration.

"They attempted to pull the two protesters from the top of the train, they then turned on me because I had two cameras on my tripod," he said.

"About 20 Londoners beat me down and I was there for several moments in the foetal position being kicked for reporting on the news, essentially.

"Luckily, three Londoners came over and got on top of me and protected me and I'm very grateful to those individuals that did that."

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British Transport Police are appealing for information and footage of the incident, with Assistant Chief Constable Sean O'Callaghan condemning the violent outburst.

"Understandably, the delay to passengers' journeys would have been annoying, but this level of response was unacceptable," he said.

"It is important that commuters and other rail users allow the police, who are specially trained, to manage these incidents."

Extinction Rebellion demonstrations were also held at Stratford and Shadwell, in coordinated disruptions at about 6.45am, local time.

Several protesters glued themselves to the trains.

'Very few' activists wanted protest to happen

In a statement, the climate action group said the train protest had received "overwhelming opposition" when it was first announced.

"This concern was communicated to the planners of the action — a very small group, which did not participate in 'national level' Rebellion decision-making bodies," an Extinction Rebellion spokesperson said.

"Some of those involved in the planning, on hearing the feedback, chose to step back from the action; but some of those involved continued and ultimately carried it out.

"Very few people in XR wanted this to happen, but the 'post-consensus' organisational model which we currently employ is such that it happened all the same."

Police said the violence from the crowd was "unacceptable". ( Supplied: Extinction Rebellion )

The statement called for activists to remember "the love that brings us together".

"These were commuters trying to get to work so they can support their loved ones," the spokesperson said.

"We recognise that disruption at Canning Town affected those already suffering the hardships of a toxic system — those who are the most at risk from the effects of climate and ecological collapse."

Tube action 'at odds' with campaign

The protests were part of a two-week campaign of civil disobedience targeting government buildings and public spaces.

Protesters are defying a city-wide ban on demonstrations, and are challenging the order in court.

London Mayor Sadiq Khan said disrupting trains was dangerous and unnecessary.

"Police arrested eight people on suspicion of 'obstructing the railway with attempt'," a police statement said.

"Despite our countless warnings, we are frustrated that Extinction Rebellion put people at risk to obstruct services on London's rail network," Assistant Chief Constable O'Callaghan said.

"Those who obstructed services are in custody and will be dealt with robustly.

"This type of action is completely at odds with what Extinction Rebellion are campaigning for and we will continue to urge them to not target any rail network."