An estimated 1,500 people attended the Kingsnorth Climate Camp in August
The widespread police use of stop and search tactics at the Climate Camp protest at Kingsnorth power station was "disproportionate", a report has found.
The South Yorkshire force's review into how Kent Police handled the week-long demonstration in August 2008 also said police lacked a "tactical plan".
But the study found the Kent force had met all of its objectives.
Liberal Democrat MP Norman Baker said the report was the "police policing themselves" and was a "whitewash".
Kingsnorth has been the focus for protests since energy company E.ON outlined plans to build a bigger coal-fired power station to replace the existing facility.
If built it would be the first new coal-powered plant in the UK for a quarter of a century.
About 1,500 protesters converged on the site last summer, prompting an operation involving some 1,400 police officers and other force staff.
The report stated: "The wide-scale deployment of stop and search tactics was both disproportionate and counterproductive."
However, it added: "No significant incursion to the island site was made (by land and water), no interruption to power supply was experienced, no serious injury or harm was caused to protester, police or public and the lawful protest by means of march and assembly was permitted and accommodated.
Stop and search disproportionate
Risk and threat level not properly assessed
Resourced from bottom up rather than top down
Absence of a tactical plan
Force met policing objectives
Protest impact on local communities minimised
Several examples of good practice
"The impact of the operation on local communities was minimised but, simply due to the scale of the operation, still remained significant."
The review also found there was a lack of a "tactical plan and strategic clarity".
Examples of good practice included health and safety risk assessment, traffic management and intelligence updates.
In response, Kent Police's Chief Constable Mike Fuller said: "While many of the recommendations made to us have already been adopted in the intervening 12 months, there is still work to be done either within Kent or in conjunction with other forces or agencies." But he added: "We have to remember that from the outset, Climate Camp was an illegal mass trespass, at short notice and without the co-operation of protest organisers.
Norman Baker MP says concerns he raised about the Climate Camp protest have not been reflected in the report
"The publicly declared aim of some protesters was to break into Kingsnorth Power Station, an action which could have had the consequence of disrupting power supplies to a great number of people in Kent.
"Despite this, Kent Police facilitated the protest over nearly a fortnight, with the help of other forces from all over the country."
The official version of events following the Climate Camp was called into question after Police Minister Vernon Coaker told Parliament that 70 officers were injured during the protests.
Following a Freedom of Information request by the Lib Dems it emerged that only 12 officers received reportable injuries, and that the figure of 70 included officers who had been bitten by insects or suffered heat exhaustion.
Mr Coaker, now minister of state for schools and learners, later apologised.
Mr Baker, the MP for Lewes, has renewed his calls for an independent review to be carried out by the Independent Police Complaints Commission.