Police are taking no further action against the woman who allegedly pushed a 52-year-old to the floor and punched her in the face.
The daughter of the victim took to Facebook after the assault to appeal for witnesses to build a case against her mother’s attacker.
Several people came forward and a 42-year-old woman from Berkhamsted was arrested after the incident in May near the Tesco Express in Northchurch.
But Herts Constabulary spokesman Giles Cooper said: “Both parties were spoken to by police, as were witnesses. No further action is being taken against the arrested woman.”
The victim – who was already blind in one eye – was left with a cut lip, bleeding around her mouth and smashed glasses after the assault.
Mr Cooper said he was not able to go into details about why no further action was taken.