A Police and Crime Commissioner who acted for miners when she was a barrister said the Home Secretary was wrong not to order an inquiry into policing at the 'Battle of Orgreave'.
Vera Baird, PCC of Northumbria Police and a former Labour MP, opposed Amber Rudd's decision not to order an investigation into what happened during a clash between picketing miners and police officers at the 1984 miners' strike.
It has emerged that the Home Office still holds around 30 files relating to the strike, some of which are specifically about Orgreave.
Ms Baird said: "I'm very concerned to hear that the Home Office holds 30 papers files relating to Orgreave and we don't know if the Home Secretary considered these before coming to her decision that no inquiry should be held.
"Let me be absolutely clear, the Home Secretary made the wrong decision, she should have allowed an inquiry so all files could be reviewed.
"Its concerns me that there are a number of files relevant to Orgreave held at the Home Office and we don't know how many of them the Home Secretary looked at before taking her decision."
The former Labour Solicitor General added: "The Home Secretary needs to answer these questions.
"In the spirit of openness and transparency she owes the miners an explanation on how she reached the conclusion that she did."
The so-called Battle of Orgreave saw the deployment of horseback charges and baton-wielding 'snatch squads' as 6,000 police officers from around the country attempted to prevent striking miners from blocking deliveries at a South Yorkshire coking plant at Orgreave.
Some 95 miners were charged with riot and violent disorder, but cases collapsed and South Yorkshire Police were later required to pay compensation.
Ms Baird represented some of the defendants at their trials.
A Home Office spokesman said: "The Home Secretary's decision was based on a number of factors, including consideration of the key purposes of an inquiry and whether these were met in the case of Orgreave.
"As part of this, the Home Secretary reviewed a range of relevant documentation."