Government officials handed confidential police intelligence about environmental activists to the energy giant E.ON before a planned peaceful demonstration, according to private emails seen by the Guardian.

Correspondence between civil servants and security officials at the company reveals how intelligence was shared about the peaceful direct action group Climate Camp in the run-up to the demonstration at Kingsnorth, the proposed site of a new coal-fired power station in north Kent.

Intelligence passed to the energy firm by officials from the Department for Business, Enterprise and Regulatory Reform (BERR) included detailed information about the movements of protesters and their meetings. E.ON was also given a secret strategy document written by environmental campaigners and information from the Police National Information and Coordination Centre (PNICC), which gathers national and international intelligence for emergency planning.

At first officials at BERR refused to release the emails, despite a request under the Freedom of Information Act from the Liberal Democrats. The decision was reversed on appeal and although large sections have been blacked out, they show:

• BERR officials passed a strategy document belonging to the "environmental protest community" to E.ON, saying: "If you haven't seen this then you will be interested in its contents."

• Government officials forwarded a Metropolitan police intelligence document to E.ON, detailing the movements and whereabouts of climate protesters in the run-up to demonstration.

• E.ON passed its planning strategy for the protest to the department's civil servants, adding: "Contact numbers will follow."

• BERR and E.ON tried to share information about their media strategies before the protest, and civil servants asked the energy company for press contacts for EDF, BP and Kent police.

Last night the disclosures were criticised by environmentalists, MPs and civil liberty groups, adding to the growing controversy over the policing of protests.

The Met commissioner, Sir Paul Stephenson, last week requested an independent review of his force's tactics, amid mounting evidence of violent behaviour by officers at the G20 protests. Two Met officers have been suspended for alleged brutality, including one who has been questioned on suspicion of manslaughter following the death of the newspaper vendor Ian Tomlinson on 1 April.

Denis O'Connor, the chief inspector of constabulary, who will carry out the review, is now expected to look at other demonstrations, including last year's policing of Kingsnorth. Further concern about police tactics emerged last week when 114 environmental campaigners were arrested in a pre-emptive raid.

David Howarth MP, who obtained the emails, said they suggested BERR had attempted to politicise the police, using their intelligence to attempt to disrupt a peaceful protest. "It is as though BERR was treating the police as an extension of E.ON's private security operation," he said. "The question is how did that [police] intelligence get to BERR? Did it come via the Home Office or straight from police? And once they'd got this intelligence, what did they do with it?"

Shami Chakrabarti, the director of Liberty, said the sharing of police intelligence between BERR and E.ON was a serious abuse of power. "The government is in danger of turning police constables into little more than bouncers and private security guards for big business. Police should be used to protect potential victims but also to facilitate people's right to protest," she said.

Kevin Smith, a spokesman for the Climate Camp, said: "The proposed coal-fired power station at Kingsnorth is a source of both international climate embarrassment to the government and reputational damage to E.ON, so it comes as no surprise that they are colluding to undermine the growing social movement of people in this country who are determined to prevent it from happening ... We demand to know who is responsible for passing on this information and see them held accountable."

One email from E.ON to BERR on 24 July gave details of the company's security strategy. In another, sent on 28 July, BERR forwards intelligence from the PNICC, detailing activists' movements, listing times, dates and numbers involved.

Last night a spokesman for E.ON said it was normal practice for energy companies to confer with "relevant authorities ... when strategically important energy assets such as power stations are being threatened with mass trespass and potentially violent closure".

He said: "We absolutely respect people's right to protest peacefully and lawfully. However, it is clear that there are some groups which very publicly aim to disrupt the safe operation of our sites, in which case our priority will always be for the safety of everyone involved."

A spokeswoman for BERR said: "Policing the climate camp protests was firmly a matter for the local police force concerned. However, given the potential threats to the security of energy supplies posed by the protests, it is only right that the government liaised with the police and the owner of the power station to exchange factual information and discuss contingency plans."