A man hurled abuse and threatened another driver in an act of 'road rage' on St John's Road.
Police are appealing for information to find the angry Audi driver.
They say he followed the while van from the Esplanade at around 11.10am on Tuesday. He overtook it and and stopped in front of it, blocking its way.
He got out of his black car and approached the van driver then swore, threatened him and made rude gestures before driving away.
The man is described as 5'10'' with black hair, a trimmed beard and tattoos on his neck.
He was wearing black joggers, a black hoodie and black baseball cap.
Anyone with information should called Police on 612612 or Crimestoppers on 0800 555 111.