Suffolk Constabulary are launching an internal inquiry into their handling of the recent Town-Norwich derby after the Canaries made an official complaint.
A spokesperson said: "The force has received an official complaint from Norwich City Football Club as well as correspondence from a handful of supporters.
"We will be examining the planning that went into the policing operation as well as focusing on the way in which travelling supporters were dealt with prior to the kick-off.
"We hope to conclude our report before the end of May, but will be meeting with club officials in the next seven days in order to agree the parameters of the inquiry.”
Norwich City chief executive David McNally stated his intention to make a complaint in a tweet a day after the match: "Really disappointed with the police treatment of our fans on Thursday night. We will be lodging an official complaint."
Around 100 Norwich fans were reported to have still been outside the ground when the match kicked off after an apparent stand-off between the two sets of fans in Portman Road.
Shortly after the game, Inspector Matthew Rose said Suffolk Constabulary were pleased with the way the derby had gone: "From my point of view the operation has been an absolute success.”
On the day of the match, police made 19 arrests and there were 13 ejections.