Alan Partridge, the controversial broadcaster whose autobiography was released earlier this month, was left red faced after reversing his Lexus into high pitched funny-man Joe Pasquale.
Both men were left shaken but unhurt after the incident in the carpark of PoundSaver in Swindown.
They had been due to cut a ribbon and welcome shoppers to the new store but Partridge was spotted arguing with Pasquale over his vocal pitch, moments before the incident.
A witness has described the incident as "hugely unprofessional".
"As Pacquale took the microphone, Partridge launched into a tirade about correct vocal pitch and delivery, referring to Joe as 'Barry White' before complaining that the microphone was missing a foam cover".
Following the incident, a Youtube video suggesting the incident "may not have been an accident" was posted but quickly removed.
In 1998 Partridge received a police caution after being spotted wearing a traffic cone on the hard shoulder of a motorway.