Full investigation underway into crowd trouble at derby between Rotherham United and Doncaster Rovers

Chief Insp Iain Chorlton, match commander for the clash at the New York Stadium on Saturday, said a group of 79 Doncaster Rovers were moved out of Rotherham town centre before them game, up to 40 supporters were ejected from the ground and four people were arrested.

He said the force were now conducting a review of the match - both to identify those involved in the disorder and to assess their approach and policing methods.

"We have started a post-match enquiry because we don't want what happened on Saturday to ruin anyone's enjoyment of football," he said.

"There were a number of issues. 79 Doncaster fans were dispersed early in the morning who had a co-ordinated plan to cause disorder. If we had not done that it would have been considerably more difficult for us to police."

Chief Insp Chorlton said the arrests were for a range of offences including drunk and disorderly behaviour and possession of class-A drugs.

He added trouble also flared during the game as well as afterwards as fans made their way home.

"During the match there were a number of incidents," he said.

"Doncaster fans ended up fighting with the stewards over a seating issue because there were too many people stood up at the front of the stand.

"We also had an issue in the Rotherham end where they seemed to be fighting among themselves and that became quite violent.

"Then after the game we had a small but violent group of Rotherham fans who broke through the metal barriers we had up to separate the fans."

Chief Insp Chorlton asked anyone with any information about disorder at the game to call 101.