The police watchdog has asked every force in the country to look through its archives for material relating to the 1984 Battle of Orgreave in South Yorkshire.
Cindy Butts, of the Independent Police Complaints Commission (IPCC), said the 65 boxes of information passed to it by South Yorkshire Police relating to the clashes between officers and striking miners was “insufficient” to make a decision over whether to launch a full investigation.
Campaigners will today protest outside the IPCC’s headquarters in Wakefield to mark a year since the actions of officers at Rotherham’s Orgreave coking works were referred to it by the force.
Television footage showed miners involved in the 1984-5 strike being beaten with truncheons by police, and a year later 95 miners, who were prosecuted for alleged rioting and unlawful assembly, were all acquitted.
Since last November, IPCC officials have been looking through more than 65,000 documents relating to clashes but have yet to come to a decision about whether a full investigation should be launched into the alleged collusion between officers.
Ms Butts, IPCC commissioner for Yorkshire, said the documentation provided so far “does not cover the complete period under consideration and it appears to be a snapshot of the events at Orgreave”.
She added that the search had been widened to cover other police forces, as well as legal representatives who represented miners in the court cases which followed Orgreave.
The IPCC was given new powers to investigate such matters in “exceptional circumstances” after the publication of the Hillsborough Independent Panel report.
Ms Butts said: “I am committed to ensuring we conduct a thorough scoping exercise to ensure we have all the information at our disposal to make a definitive decision about what matters remain capable of investigation.”
Members of the Orgreave Truth and Justice Campaign (OTJC) will picket the watchdog’s offices in Wakefield at 1pm today.
A spokesman said: “One year on there is no indication of how long it will take for the IPCC to examine all the police files and the OTJC remains concerned that no officers will face charges of assault, perjury, perverting the course of justice and misconduct in a public office.”