An English Defence League (EDL) protest in Leicester city centre cost taxpayers more than £850,000, the BBC has learned.
Thirty-six people were arrested after last October's demonstrations.
The cost of policing the event amounted to £715,000 while the city council said it had been faced with a £137,000 bill.
Riot police were deployed during the protest in what was the city's largest policing operation for 25 years.
About 1,000 English Defence League (EDL) supporters held a rally in the city on 9 October while Unite Against Fascism (UAF) staged a rival protest.
Leicestershire Constabulary said the majority of its £715,000 was spent on staffing.
Twelve other forces were brought in to assist with the policing of the event with more than 2,000 officers involved in the operation.
Ch Supt Rob Nixon said: "It's a huge amount of money but when we compare ourselves with other cities it is actually comparatively low.
"At the moment it's come out of the police reserves but we're obviously working with the local authority and exploring all opportunities for trying to recoup the costs.
"I'd like to say I'm optimistic about that - but clearly we're not on our own.
"Other forces up and down the country have also incurred similar if not more costs, so if you combine that all of those forces will be looking to recoup a large amount of money.
"While it is right and proper that we try and recoup it I'm not very optimistic that we'll get that in the short term."
Leicester City Council said its costs were incurred in making sure the city was safe on the day.
Chief executive, Sheila Lock, said: "We could have done without the cost, definitely.
"A portion of costs was attributable to activities we organised for young people to divert them away from flashpoints on the day.
"And then of course we held a celebratory event on the Sunday which I think people in Leicester felt was very important to kind of give people a real message of what Leicester was about."