Photographs show the alleged Remain activist arguing with a UKIP party member moments before the altercation between the two women broke out.
It is not known who initiated the fight, but the woman identified as the Remain supporter grabbed at the sweater of the woman attending the UKIP event and both fell to the ground.
UKIP and the Remain campaign group have both denied either of these women were their supporters.
One man attempted to break up the fight whilst another man, wearing a striped scarf and a grey jumper, stood between the women.
Both were later seen with bloodied faces.