Nearly 80 people were arrested and three police officers left needing hospital treatment during a huge climate change protest at a power station.
More than 1,000 demonstrators converged on the giant coal-powered Ratcliffe-on-Soar site in Nottinghamshire yesterday, with clashes breaking out between police and protesters as they tried to tear up perimeter fencing.
One policeman was airlifted to hospital with head injuries but later released, and two other officers needed hospital treatment for minor injuries, Nottinghamshire Police said.
Police said nearly 80 people were arrested during the day on suspicion of committing offences including aggravated trespass and criminal damage.
"There are still a large number of protesters at the power station and we will continue to monitor the situation throughout the night," a spokesman said,.
Demonstrators, under the banner the Great Climate Swoop, included supporters of three pressure groups - the Camp for Climate Action, Plane Stupid and Climate Rush.
The 2,000MW coal-fired power station is owned by the energy company E.ON and said to be one of the largest producers of carbon dioxide in Britain.
Some protesters carried banners and cardboard gravestones bearing the words 'RIP E.ON' and 'RIP Ratcliffe'. Many chanted "F off, E.ON" and some wore T-shirts emblazoned with the slogan.
Many protested peacefully at the power station's main entrance, but police said breakaway groups had assaulted officers and pulled down security fences - with some managing to gain access to the heavily-guarded site.
Ten people - seven men and three women aged between 19 and 53 - were arrested before the protest began on suspicion of conspiracy to commit aggravated trespass at the power station.
During the course of the day, as numbers at the site grew, dozens of others were detained after police said they had been forced to "alter" their marshalling of the protest.
The force spokeswoman said: "Police have experienced concerted and determined efforts to tear down perimeter fencing.
"Some officers at the fences have been assaulted and, while some protesters managed to enter the site, police remain in control of the site.
"Protesters and the public should be aware that police have had to alter their policing style in response to concerted efforts to tear down perimeter fencing and enter the site."
Protesters, who said they plan to demonstrate at the plant through the night, were undeterred by the police warnings.
Activist Joanna Gonzales, from the Camp for Climate Action said: "It has been inspiring to see so many people who are prepared to take direct action and face arrest to show that this power station needs to closed for good.
"The Swoop shows the movement against coal power is strong and growing fast. We hope even more people will get involved as we gear up towards the UN climate summit in Copenhagen."
Ratcliffe-on-Soar was chosen as the activists' target in an online vote following the Climate Camp held in London in August, with some threatening to break into the site and close it down.
The Camp for Climate Action later issued a statement wishing the officer who sustained head injuries a "speedy recovery".
The group said it had no details about the incident, adding: "The Camp for Climate Action is at Ratcliffe to confront the causes of climate change, not get into conflict with the police."
A spokesman for the E.ON, which was granted a High Court injunction giving police the power to arrest anyone trying to enter the site, said: "Ratcliffe power station plays a key role in ensuring we keep the lights on for millions of homes across the region and has undergone major investments that make Ratcliffe one of the cleanest power stations of its kind.
"We're already closing three of our other fossil-fired power stations and are pushing forward with lower carbon options that include developing new wind farms, gas plants, cleaner coal and nuclear that will allow us to tackle the threat of climate change while also ensuring security and affordability of energy supplies."