A former police officer who was at the 1984 "Battle of Orgreave" says police had been told to use "as much force as possible" against striking miners.
Police clashed with miners at the Orgreave coke plant in South Yorkshire, on 18 June - and campaigners want a new inquiry into policing on the day.
The ex-Merseyside constable told the BBC senior officers "were anticipating trouble and in some ways relishing it".
South Yorkshire Police said it would "fully participate" in any inquiry.
Miners had been on strike over fears that pits would be closed and jobs lost.
They picketed other mines and plants to try to get other workers to support the strike, something the government said was a threat to the rule of law and to the right of others to go to work.
Trouble erupted at Orgreave when picketing miners tried to stop lorries leaving the plant. The stand-off between miners and police erupted into a running battle with injuries on both sides.
There have been questions over who sparked the violence and whether the police used excessive force, during what was the most violent confrontation of the 1984-85 miners' strike.
The Orgreave Truth and Justice Campaign has been pushing for a new inquiry into the policing at Orgreave.
Home Secretary Amber Rudd has promised she will announce whether there will be an inquiry into the clashes by the end of October.
Speaking to the BBC, the officer - who asked to remain anonymous - said senior South Yorkshire Police officers briefed them the night before the 18 June clashes.
He was among about 6,000 officers called in to bolster police ranks protecting the Orgreave coke works.
"They were anticipating trouble and in some ways relishing it and looking forward to it," he said.
"It was a licence to do what we wanted, which I didn't think was right because we didn't know what was going to happen."
He said officers had been ordered to charge a largely peaceful crowd.
"There were running battles and miners were falling over and police officers were batoning them," the officer said.
"I couldn't believe what I was seeing. I was just seeing police officers attack people. These were people on the ground and even if they weren't doing anything - just walking away - police officers had their batons and they were just hitting people."
Stefan Wysocki was one of the 95 miners who was arrested at Orgreave. He was accused of throwing a stone.
He said: "They marched me back down the hill to the line of police officers with shields and bounced me off them. The line opened up and they knocked ten bells of crap out of me. I was punched and kicked."
Most of the miners were charged with riot or unlawful assembly.
They had faced long prison sentences, but the case collapsed in court a year later and they were all cleared. There have been allegations that police officers had been told what to write in their statements to justify more serious charges.
Norman Tebbit - now Lord Tebbit - who was in former Prime Minister Margaret Thatcher's cabinet during the strike, said: "They [the miners] think it was their right to use violence to stop people from going to work. It wasn't.
"It's clear. What's the problem? The problem for them is they lost their battle - a violent battle - to overthrow the rule of law."
Lord Tebbit said the so-called Battle of Orgreave should be left to history and a new inquiry would be "a waste of time and money".
"The facts are absolutely clear; they are well-known."
South Yorkshire Police - the force in charge on the day - said in a statement: "We are acutely aware of the impact such long-standing unanswered questions can have on those directly, and indirectly, affected by this incident.
"Should there be an inquiry then we will fully participate to help find answers to those unanswered questions."