The police match commander for last night’s Sheffield derby has promised a full review of police planning for similar fixtures in the future.
Chief Superintendent and Match Commander Shaun Morley was in charge of the policing operation for the 131st competitive match on Monday night.
The run up to the game passed off largely trouble free, but violence flared outside the ground after the match finished as rival supporters came together near Leppings Lane.
A number of arrests were made and at least one person suffered a serious injury to his eye.
Speaking after the game, Chief Superintendent Morley said: “Last night there was the charged atmosphere that you would expect for a derby and the majority of fans enjoyed their evening, passionately supporting their team and didn’t cause any issues whatsoever.
“We are aware of the disorder as people left the stadium, where we saw a small minority of fans take the opportunity to launch missiles at rival fans, causing injury and significant concern.
“This is unacceptable behaviour and will not be tolerated. Arrests were made and we will continue to actively seek to identify those involved.
“As with any large scale operation such as this, we will be completing a full review of the police planning for the match last night, to ensure lessons can be learned ahead of similar fixtures in the future.
“As part of this, we are talking with supporters groups from both teams.”
After the match fans took to social media to complain about the policing operation, saying it had contributed to the trouble that resulted.
Blades fan Pete O'Leary, who watched the game from the upper tier of the Leppings Lane end, said he feared a supporter could be seriously injured or even killed if lessons weren't learned.
He said: "When we finally got onto Leppings Lane both sets of fans became mingled together and kids were getting crushed and kicked all over the place.
"I and a few others managed to push a few families away towards the coaches for safety, and we literally had to push them as the crush was that bad.
"Kids and women were petrified and the police just stood back. I saw two blokes with blood pouring from their heads being treated.”
And Wednesdayite Ann-Marie Whittaker described her own experience as “horrible”.
“I’ve been going home and away following Wednesday all my life, and my two girls have had a season ticket since the ages of four and five,” she said.
“We have never witnessed anything like this, and the girls are really shaken up by it.
“We were lucky those United fans helped us out of the crowd otherwise I don't know what would have happened.”