England fans have expressed concern over possible violence in Donetsk tomorrow night if Roy Hodgson's side beat Euro 2012 co-hosts Ukraine.
There will be an intense atmosphere inside the Donbass Arena as Ukraine need a victory to reach the quarter-finals whereas a draw will be good enough for England to progress.
The head of the British police contingent at the tournament admitted it will be a "challenging operation" to ensure England fans are "appropriately policed".
In addition to the passionate home support, the number of Russians wearing England shirts also presents a problem.
Assistant Chief Constable Andy Holt, of the Association of Chief Police Officers, which is leading the 18 British officers in Ukraine, said he had prepared for the possibility of the match being an intense affair.
"We always knew that if England end up in the last game of the group stage playing Ukraine and both need something out of the game, it would be a very tense atmosphere," he said. "This will be the most challenging operation in Ukraine thus far and we'll be working really hard with our Ukrainian colleagues to do all we can to make sure that England supporters are safe and appropriately policed."
Mr Holt raised concern over the vast amount of Russians who are wearing England shirts at Euro 2012. Russian supporters were involved in violent clashes with Polish fans and riot police ahead of their match in Warsaw last Tuesday.
"It poses a challenge because some Russian fans throughout this tournament haven't behaved particularly well," Mr Holt said. "What I don't want is Russian fans wearing England shirts misbehaving, and then England fans being blamed."
Meanwhile, Uefa has opened disciplinary proceedings against the Football Association (FA) for the "inappropriate conduct" of England supporters during Friday's match against Sweden.
They are investigating an attempted pitch invasion by fans during the 3-2 win at the Olympic Stadium in Kiev. England's second and third goals resulted in a handful of supporters climbing over a barrier. But it is understood the FA will argue there was no intent to invade the pitch and it was simply supporters showing their exuberance.