Template:Infobox character Detective Constable Joanne Masters is a fictional character in the long-running ITV police drama The Bill. She is played by Sally Rogers. Because she is a CID officer she does not have a callsign and is referred to in radio communications simply as 'DC Masters'.
Jo was brought into Sun Hill by Superintendent Adam Okaro, who had plans for her to defuse the tension between CID heads DCI Jack Meadows and DI Neil Manson. It was immediately clear that Jo had sustained somewhat of an infamous reputation at her previous stations, partially because her former senior officer could not abide her. A capable detective with several years' experience, Jo had her chance to shine almost instantly when both her superiors were caught up in a hostage situation, and being that she is a skilled hostage negotiator she was brought onto the scene. When the situation was finally over and her superiors are freed, they both agree that Jo handled the situation well, to which Okaro remarks that it is the first time either of them have agreed in a long time, implying she had succeeded in his original mission for her.
Headstrong, lively and motivated, Jo is a no-nonsense copper who is there to get a result and does not really care about who she offends in the process. When DS Samantha Nixon goes behind her back to speak to her exclusive supergrass Seth Mercer, frightening him off and putting his life in danger by doing so, Jo ignores the fact that Nixon is her superior and challenges her actions. In doing so, Jo also gives friend and colleague T/DC Gary Best the courage and inspiration to lodge a complaint against another colleague he believes to be bullying him, which shows just how influential Jo's actions are. Having made a lasting impression at Sun Hill, it is no surprise when Jo is chosen to be the contact officer for a recently released child serial killer. After having formed a bond with the woman, Jo uses the link with the woman to her advantage when she goes undercover in prison to discover how drugs are being sold on the wing. Jo is an out-and-proud lipstick lesbian and is in a long-term relationship with a woman named Tess. Later, Jo's commitment to the job and just under a year working undercover in another district causes the two of them to separate. Jo also has a softer, playful, kindly side and a warm sense of humour, which she tends to reveal only to her closest friends: DS Phil Hunter and Stuart Turner.
When Seth Mercer contacts Jo once more with information that his company is being exploited by business partners, she is convinced to go undercover on a long-term operation in Nottingham CID. Although her undercover operation results in the death of Seth Mercer and Phillip Hanson, Jo returns to Sun Hill.
Later, Jo is kidnapped and held hostage at gun point by Crime Scene Photographer Rachel Inns, after Jo collects enough evidence to arrest her on the suspicion of the murder of Cindy Statham. Larry Franks previously made a statement confessing to the murder, but after he withdraws his confession, Jo is determined to clear Larry's name and prove to DI Manson that he is wrong.
Jo also helped collague Stuart Turner when he was being blackmialed by 'The Postman', a drug dealer in Sun Hill. She also has respect for her Senior Officers and her colleagues. She is sometimes known to put her career on the line if she can help them, though she tries to avoid this.