Hillsborough match commander David Duckenfield has accepted his failure to close the tunnel was the direct cause of the death of 96 people in April 1989.
Giving evidence during the new inquest into the disaster, Mr Duckenfield said it had been the most difficult period of his life to admit his professional failing led to the deaths.
The officer in charge of policing at Hillsborough has denied being part of a cover-up after the disaster.
Cross-examined by Rajiv Menon QC on behalf of the victim's families, David Duckenfield told the inquest that he had made a 'mistake' but denied being 'negligent' and causing the deaths of 96 Liverpool fans.
ITV News reporter Damon Green reports.
Hillsborough match commander accepts his failure to close the tunnel was the direct cause of the death of 96 people in April 1989.
The police match commander at Hillsborough has said he thinks there was no conspiracy about the disaster.