Police behaviour with protesters has not changed since the miners’ strike, campaigners for the newly announced inquiry into Orgreave have said, as they warned of potential “further injustices”.

Speaking at a press conference after Labour revealed it would hold a statutory inquiry into violent policing at the picket, the Orgreave Truth and Justice campaign said lessons had not been learned since that day 41 years ago.

“We look now at all the demonstrations, the rallies, the peaceful protests that are going on all the way through [history, since Orgreave] and happening now … if you look at what happened at Sarah Everard, if you look at what’s happening now in London on the Palestinian demos, if you look at what happens behind the scenes on ordinary pickets, police behaviour [has not changed],” said Chris Hockney, one of the campaigners.

“Basically, they are there as agents of the state, and we end up seeing it time after time after time. And there will be further injustices perpetrated because the police do what they do.”

Under the government of Margaret Thatcher in the early 1980s, the Home Office and senior police officers created a secret tactical manual that redefined what could be considered “reasonable force” when it came to protesters. For example, it allowed mounted police charges into static crowds and the use of short shields and truncheons to “incapacitate” non-violent protesters.

These additional unprecedented powers, described as “paramilitary” tactics, have still not been repealed, despite never having parliamentary approval. Another campaigner, Chris Peace, added: “I think the issue is when policing gets political, and the policing at Orgreave was politically led. I think that’s an important point to make.”

The clash between police and striking miners on 18 June 1984 at the Orgreave coking plant in South Yorkshire represented a “turning point”, they said, in the police’s use of force to shut down protest.

While Thatcher maintained that the government had not interfered in policing of the miners’ strike, various Home Office documents have since revealed extensive active interference, including influencing, directing and financially supporting the police in their actions against striking miners.

Speaking before the press conference, the mayor of South Yorkshire, Oliver Coppard, said the police were under “completely new” leadership in South Yorkshire compared with the days of the strike.

“I’m conscious that in South Yorkshire and across this country we have any number of challenges when it comes to policing protests, because these things are always difficult. But I think what we saw on the day at Orgreave was a million miles away from the way in which protest is policed now.”

He added that the Orgreave inquiry was important “because we need the truth and we need accountability and we need justice to be done”.

However, police in South Yorkshire were not as welcoming, with the Police Federation stating that local operations were already at “breaking point”. The chair of the police-staffing association in South Yorkshire, Steven Kent, said: “Courageous colleagues are out there keeping the public safe struggling with what feels like one arm tied behind their backs as government cutbacks to the service hit home.

“This will be long and protracted – and the associated costs of this inquiry will lead to there being even less money in the policing purse, which will only have a negative impact on the public of South Yorkshire.”

One of the 95 miners arrested at Orgreave, the campaigner Kevin Horne, said the inquiry would not “make the wrong thing right”, but that it could help mining communities “get back to something normal again”.

He said: “We have this chance now of wiping the slate clean so that our children and grandchildren can respect the police again.”