Sergeant is a rank within the police force. The most well known Sergeant is SRU Team One Team Sergeant, Gregory Parker. Another mentioned Sergeant is Sergeant Troy (Unknown Surname). Yet another Sergeant was Roland Cray, promoted in Episode:Scorpio. Spike's mentor Oliver McCoy, was also a Sergeant. At the end of the series, Constable Ed Lane was promoted to Sergeant in Team One at the end of the series.
Trivia: Greg was the Team Sergeant for Team One. Troy was the Sergeant for Team Four. Team Three's (which was mentioned several times) Sergeant was never mentioned, despite Donna Sabine being its Team Leader. Team Five's Sergeant was also not known.