Police officer
Police officers were employees of the police force. They were also called cops, coppers, bobbies, policemen or policewomen.
Constable was a rank of police officer, (TV: Everything Changes, The Cambridge Spy et al.) as was Sergeant. (PROSE: Long Time Dead)
Mason was a police officer in 1955 Montgomery, Alabama. (TV: Rosa)
Gwen Cooper was a police constable before joining Torchwood Three. (TV: Everything Changes)
Andy Davidson, Gwen's former police partner, and ally to Torchwood, (TV: Adrift, The Blood Line, AUDIO: More Than This, et al.) was promoted to Sergeant by the time he resigned from the force. (AUDIO: The Empty Hand, PROSE: Long Time Dead)
When she met the Thirteenth Doctor, Yasmin Khan was a junior police officer with Hallamshire Police, in her second year of probation. (TV: The Woman Who Fell to Earth)