Green Party MP Caroline Lucas was arrested today after taking part in anti-fracking protests.
Ms Lucas was among a number of people arrested after staging a protest outside the gates of energy firm Cuadrilla's drilling site in Balcombe, West Sussex, as hundreds demonstrated against fracking.
The arrests come as protesters who oppose the controversial process for extracting shale gas blockaded the headquarters of Cuadrilla while others superglued themselves to a PR company used by the energy firm.
The action at Cuadrilla in Lichfield, Staffordshire, at PR firm Bell Pottinger in central London, and Balcombe comes on the first of two days of "mass civil disobedience" which campaigners have pledged to carry out to highlight their stance against fracking.
The MP had been sat with a crowd of protesters outside the entrance to the site for most of the day when she was marched away by officers and put into a waiting police van.
Protesters could be heard announcing over a megaphone that the MP for Brighton Pavilion had been arrested. They also claimed that Lucas's son was arrested earlier.
The arrest came as police tried to move those who had set up outside the entrance to the designated protest area nearby.
They were warned earlier by officers that they risked arrest if they failed to comply with the public order notice they were presented with earlier.
While some protesters went peacefully others were carried away by officers into police vans.
Activists are taking part in a six-day Reclaim The Power action camp in Balcombe, West Sussex, after Cuadrilla began carrying out exploratory oil drilling at the site.
Hundreds of campaigners staged noisy protests in Balcombe in the face of a heavy police presence.
Protest group No Dash for Gas accused police at Balcombe of "an extremely aggressive response" to the demonstration, claiming officers charged, shoved and kettled protesters, including disabled people and children
Protester Ewa Jasiewicz said: "This is an outrageously aggressive response to a day of principled civil disobedience. All of our actions have safety, dignity and respect at their core.
"Cuadrilla and the Government were desperate to discredit fracking opponents. We offered them no aggression so they are creating it themselves."
Earlier, Sussex Police said on Twitter: "We would like to reiterate that protesters aren't being kettled and are free to leave the site as they wish."
Staffordshire Police said they arrested a 36-year-old woman from Middlesex on suspicion of aggravated trespass at the protest at Cuadrilla's headquarters in Lichfield.
"Officers remain at the site to ensure the protest remains lawful, peaceful and safe, and we're working closely with the business and the protesters," a spokeswoman said.
At the protest at Bell Pottinger's offices, City of London police arrested six people on suspicion of aggravated trespass. Two of the six were also arrested on suspicion of criminal damage.
As she was arrested at Balcombe, Ms Lucas said: "Along with everyone else who took action today, I'm trying to stop a process which could cause enormous damage for decades to come.
"The evidence is clear that fracking undermines efforts to tackle the climate crisis and poses potential risks to the local environment.
"People today, myself included, took peaceful non-violent direct action only after exhausting every other means of protest available to us.
"I'm in the privileged position of being able to put questions to the Government directly and arrange debates in Parliament, but still ministers have refused to listen.
"Despite the opposition to fracking being abundantly clear, the Government has completely ignored the views of those they are supposed to represent.
"When the democratic deficit is so enormous, people are left with very little option but to take peaceful, non-violent direct action."
Protesters also said they had staged a demonstration outside the home of former energy secretary and Chancellor George Osborne's father-in-law Lord Howell, erecting an estate agent-style "For Shale" sign.
Lord Howell caused a furore recently when he said fracking should go ahead in the North East because it had ''large and uninhabited and desolate areas'', before claiming he had meant the North West.
The campaigners also put up a banner which read "Not in your back yard, Lord Howell? Frack off!", and delivered a letter telling the peer his home had been designated as a "desolate dwelling" and fracking would commence in 10 days.
Guy Shrubsole, from Reclaim the Power, said: "Fracking shouldn't happen in anyone's backyard - it's hugely dangerous, will shatter communities and will release vast quantities of climate-changing gases.
"Lord Howell's arrogant and ignorant recent comments show how wrong politicians are if they think they can railroad fracking through Britain's communities.
"But they're in for a shock, because as the battle for Balcombe shows, a massive popular rebellion is brewing on their doorsteps."
Police said around 25 protesters had been arrested in Balcombe by around 3.30pm, as officers moved in to clear a large group of people in front of an emergency access to the Cuadrilla drilling site.
Sussex Police said officers had earlier removed a number of bicycles that had been locked together and left lying across the road, which they said created a "serious safety hazard" to the gathered demonstrators.
Superintendent Lawrence Hobbs from Sussex Police said: "We had been expecting some form of direct action today and we had officers in place ready to deal with it. It has been necessary to close the road, but that has been done a number of times in recent days to ensure that safety of all those who are taking part.
"As we have said from the very start of this protest operation, we are more than happy to facilitate peaceful protest, but those who are intent on criminal action will be arrested."
Sussex Police said m ore than 400 officers have been deployed on the operation at Balcombe, with support from 10 other UK forces.