Who is Detective Sergeant Barbara Havers from A Great Deliverance and what is their importance?

Havers is painfully aware of her status as persona non grata at CID. She is somewhat difficult to get along with, due to the fact that she does not think very highly of herself. Sergeant Havers was demoted and sent back to uniform detail. The Teys case is an opportunity to redeem herself in the eyes of her CID superiors but Havers is confused as to why she has been assigned to work with Inspector Lynley. Havers resents Lynley, believing him to be a snob born with a silver spoon in his mouth. She sees Lynley's career at New Scotland Yard as something he does for entertainment rather than anything serious. Havers realizes that she is rather unattractive and this fact gets in the way of her forming a closer professional relationship with Inspector Lynley. Deep down inside, Havers secretly wishes that Lynley would find her attractive as well. Havers becomes jealous when she discovers that Lynley has spent the night with Stepha Odell. Eventually, however, Havers comes to view Lynley as something of an anomaly and a member of the upper crust who is actually a decent human being.