Campaigners have staged a noisy demonstration outside the Home Office to step up calls for an inquiry into the policing of picketing during the miners' strike in the 1980s.
The 'Battle of Orgreave' saw police deploy horseback charges and baton-wielding snatch squads as 6,000 officers from around the country attempted to prevent striking miners from blocking deliveries at a coking plant near Sheffield in 1984.
Some 95 people were charged with riot and violent disorder, but cases collapsed and South Yorkshire Police were later required to pay compensation.
Hundreds of trade unionists, supporters and former miners joined the protest outside the Home Office in Westminster, as well as politicians including Shadow Home Secretary Diane Abbott.
Dubbed the Make A Noise protest, they blew whistles and horns and banged drums.
Joe Rollin, an official with the Unite union, who chairs the Orgreave Truth and Justice Campaign, told the crowd: "We want to send a clear message to the Home Secretary and the Tories that we aren't going away and that our fight for the truth will go on.
"We know why the police acted as they did on that day - they wanted to send a message to the trade union movement. Our communities have lived with the consequences ever since."
Mr Rollin read out a series of statistics from the year-long strike, including 165,000 miners on strike, 11,313 arrested, 7,000 injured and 960 sacked.
Chris Skidmore, Yorkshire area chairman of the National Union of Mineworkers, who was at Orgreave, said: "We want to heighten awareness of what happened and the justice of our case for an inquiry."
Newly declassified files published last week showed that Margaret Thatcher's government feared a witch hunt would ensue if a public inquiry was held into policing during the year-long strike.
Leon Brittan, then-home secretary, told a 1985 meeting that the "Government should not encourage any form of enquiry into the behaviour of the police", believing it would "turn into a witch hunt" with an 'anti-police bias', according to 18 files released to the National Archive.
The documents were released after Home Secretary Amber Rudd ruled out an inquiry. Further files are expected to be released as Ms Rudd previously said a total of 30 files would be made public.
Diane Abbott said: "Labour fully supports the demand for justice for the striking miners at Orgreave and their families. The truth must be told, but the Tories are refusing to hold a proper inquiry.
"Labour has consistently argued you can't understand what happened at Hillsborough unless you get to the bottom of Orgreave. It was the same force, the same leadership and very similar methods in the aftermath.
"The Government is stonewalling despite previously indicating that a full Inquiry was on offer. Many campaigners believe this is because political direction was involved, that the Thatcher Government used the police to crush the miners. We support the campaigners in their continuing demand for justice."