The Met Police are investigating after footage emerged of a Millwall fan punching a Tottenham supporter in the face following Sunday's FA Cup tie at White Hart Lane.
The seven-second video clip, which was widely circulated on social media, shows two Tottenham fans singing 'we f***ing hate Millwall' following their 6-0 quarter-final win to rival fans walking past.
One Millwall fan then emerges from the group and hits one of the pair hard in the face, sending him tumbling to the ground, to cheers from those going past.
Met Police 'confirmed that the video circulating on social media has been reported to police'.