Sheffield's police chief has issued a warning to suspected football hooligans considering committing crimes on Steel City derby day.
Months of planning by South Yorkshire Police has gone into policing today's match between Sheffield Wednesday and Sheffield United at Hillsborough.
Sheffield’s District Commander Chief Superintendent Shaun Morley said officers will take 'effective action' against anyone committing anti-social behaviour or disorder.
He said: "The one message I do want to get across to a few individuals who will probably be contemplating getting involved in anti-social behaviour, disorder or conflict.
"For those individuals my message is this - please do not bother because we have a very well planned and effective policing operations and we will take very positive, effective action if you choose to engage in anti-social behviour or disorder.
"I am hoping that won't be the case but if it is please expect that you will probably be arrested or we will intervene with you positively.
"That aside I am hoping that everyone has a very enjoyable and safe day."
Hundreds of officers have been on duty from early this morning.