LONDON, ENGLAND - FEBRUARY 18: Police horses called in to help calm the pitch invasion by Millwall fans during the Emirates FA Cup Fifth Round match between Millwall v Leicester City at The Den on February 18, 2017 in London, England. (Photo by Craig Mercer - CameraSport via Getty Images)

LONDON, ENGLAND - FEBRUARY 18:  Police horses called in to help calm the pitch invasion by Millwall fans during the Emirates FA Cup Fifth Round match between Millwall v Leicester City at The Den on February 18, 2017 in London, England. (Photo by Craig Mercer - CameraSport via Getty Images)