List of Midsomer Murders characters
Detective Chief Inspector Thomas "Tom" Geoffrey Barnaby (John Nettles) (series 1-13)—A senior member of Causton CID, Barnaby formerly worked for MI6. A patient, tolerant man, Barnaby's style of investigation is methodical and fair. Barnaby is a sagacious and perceptive individual, able to recognise seemingly obscure clues. Barnaby's social life revolves around his wife Joyce and his daughter Cully, who often provide a personal connection with the crimes that he is investigating. Barnaby's parents are both deceased by the episode "Blue Herrings". In his last appearance, "Fit for Murder", we learn that his father died on his birthday, at Barnaby's current age.
Detective Chief Inspector John Barnaby (Neil Dudgeon) (series 13, series 14-present)—Barnaby transferred from Brighton to Midsomer's Causton CID to replace his older cousin, Chief Inspector Tom Barnaby, when Barnaby retired. He has a degree in Psychology from Durham University, which earned him some ribbing from DS Jones when he first arrived; however, despite a rocky start, the two make a formidable team. Barnaby lives in a large country cottage with his wife Sarah and their dog Sykes. He first makes a guest appearance in the series 13 episode, "The Sword of Guillaume" before taking over in the series 14 premiere, "Death in the Slow Lane." Dudgeon actually made his first appearance on the show not as John Barnaby, but as womanising gardener Daniel Bolt in the series 4 opener "Garden of Death".
Joyce Barnaby (Jane Wymark) (series 1-13)—DCI Tom Barnaby's long-suffering wife. She is tolerant of her husband, despite his being a workaholic who spent their honeymoon solving the case of the "Pimlico Poisoner", which suggests that they met in London. Joyce is an easy-going and friendly woman who likes to be involved in community activities. She has long possessed a desire to move out of their Causton home and into one of the picturesque Midsomer villages—only to be put off by the grisly murders that occur there. She's known to her family as an experimental, but not always successful, cook. Thus, Tom is often seen taking advantage of every opportunity to dine out. She married Tom in 1973 and their only child, Cully, was born five years later in 1978. Her parents are called Muriel and Douglas.
Sarah Barnaby (Fiona Dolman) (series 14-present)—John Barnaby's wife is the headmistress of the local primary school. As she has a full time career of her own (unlike Joyce), she does not figure as much in her husband's cases; and they don't have any children (until the end of the sixteenth series), although you may consider Sykes, their dog, as their child. Despite this, they have a loving marriage and celebrated their fifteen year anniversary in "Schooled for murder". Throughout the sixteenth series Sarah is pregnant and in the last episode of the series she gives birth to their first child, a daughter, called Betty.
Detective Sergeant (later Inspector) Gavin Troy (Daniel Casey) (series 1-6, series 7, series 11)—DCI Barnaby's first assistant. Troy is bright and ambitious. Early in the series, Troy is also known for his careless driving, causing a number of near-accidents (which does not stop at all, even in his final/guest appearance). Troy is also prejudiced towards gay people (in the very first episode, "The Killings at Badger's Drift", he shows his discomfort by using a slur against the gay undertaker) and the elderly, referring to them as "wrinklies". In "Market For Murder" and "Destroying Angel" Troy provides valuable insight, finding out how the killers committed the murders, so oddly it was not Barnaby who solved those cases. In "Painted In Blood", Barnaby is forbidden to take part in the investigation, but Troy supplies him with information. Later on, Barnaby is taken hostage in a bank robbery and might have died until Troy sneaked in and attacked the robber, yet at the same Troy would himself have been killed had Barnaby not stepped in, but together they overpower the robber. Troy's relationship with Barnaby is warm, and the two make a formidable pair. Troy was promoted to Inspector and transferred in the first episode of the seventh series, called "The Green Man". Troy makes one re-appearance in the first episode of Series 11, "Blood Wedding", to attend the wedding of Tom's daughter, Cully Barnaby (whom he once secretly kissed, which temporarily strained his relationship with Barnaby), where he met his second successor, Sgt Jones.
Detective Sergeant Daniel "Dan" Scott (John Hopkins) (series 7-8)—is a lot cockier than his predecessor DS Troy; he is a Londoner who was not thrilled at being transferred from the Metropolitan Police Service to Midsomer, which he regards as the "sticks". His relationship with Tom was prickly at first; but it mellowed into a slightly awkward marriage of convenience, with Barnaby still disapproving of Scott's methods and Scott grudgingly starting to respect Barnaby. Unlike Troy and Jones, Scott did not have a warm relationship with Barnaby, and he is Barnaby's shortest serving partner. In "The Straw Woman", Scott develops a love interest who is brutally murdered. Scott's departure from the show was abrupt. In "The House in the Woods", Barnaby describes Scott as having called him to say he was ill and thus unable to come to work. Barnaby invites Ben Jones to assist him on that case. After this incident, no more is heard from Scott, and Jones becomes the new deputy.
Detective Sergeant (later Inspector) (previously Police and Detective Constable) Benjamin "Ben" Jones (Jason Hughes) (series 9-15)—Jones is Tom Barnaby's third junior. Unlike Troy and Scott, who first appeared on the series as plain-clothed detective sergeants, Jones was a uniformed police constable when he was first introduced. Jones was first appointed as a Detective Constable, as well as Barnaby's second-in-command. (after assisting Barnaby during Sgt Scott's absence) and promoted to Detective Sergeant by the end of his first series. Jones is considerably less naive than Troy or Scott, possessing an insight into cases that neither would have. Jones was born in Wales and remarks about his love for Wales when he and Tom travel there in the episode "Death and Dust". He is formerly a Freemason, as revealed in "King's Crystal". In the episode "Death in Chorus", Jones exhibits a remarkable vocal talent and is recruited to sing tenor in the Midsomer Worthy choir. In "Death in the Slow Lane", it is revealed that Jones was interested in replacing Tom Barnaby upon his retirement and was a little put out by his cousin, John Barnaby, being transferred to the position instead. In reality, he could not have been given the post because it would have required him to bypass the rank of inspector. In "Murder Of Innocence", it is revealed that Jones is in a relationship with firefighter Susie Bellingham. In the series 16 opener, "The Christmas Haunting", it was revealed that Jones had been promoted to Inspector and transferred to Brighton. He sent a Christmas card to the Barnabys, though it was addressed to their dog, Sykes.
Detective Sergeant Charlie Nelson (Gwilym Lee) (series 16-present)—When Jones was promoted, he was replaced by DS Charlie Nelson. Nelson is the first Sergeant to not serve alongside Tom Barnaby. He is a lodger at Kate's house.
Doctor George Bullard (Barry Jackson) (series 1-14)—Causton's resident pathologist. Bullard goes about his work with a professional skill and a cheery personality. He is a good friend of Tom Barnaby's and has been a regular throughout the series (save for a brief spell, when his place was taken by Dr. Dan Peterson played by Toby Jones). In later episodes, Bullard has often played a greater role in the plot, even making a sterling appearance in the Midsomer Worthy Choir in "Death in Chorus". In one episode, he admits to the "accidental" death of his wife while on tour at a slaughter house. At the end of "The Oblong Murders", Bullard tells Barnaby that he's going to take some time off: "I've decided to do some fishing. Like Tom. He suggested a holiday in Ireland.", which is most likely his retirement (like Tom).
Doctor Kate Wilding (Tamzin Malleson) (series 14-present)—Dr George Bullard's replacement as resident pathologist. Her confident, competent, no-nonsense approach has earned the detectives' respect. She is unmarried and is also a professor. Her parents Giles and Laura, have appeared in one episode, "The Flying Club". 
Constable Gail Stephens (Kirsty Dillon) (series 10-13)—a colleague of Tom Barnaby and DS Jones, who often helps them in their cases, sometimes providing valuable insight. Gail was transferred to Midsomer from Binwell. Gail is cheery but emotional, breaking down in tears when, after initially serving as a uniformed woman police constable, she was appointed as a plain-clothed CID detective. Throughout Gail's appearances, it is implied that she is on the point of having an affair with Sgt Jones, but when it came to the crunch he decided that he did not want to get too heavily involved with a work colleague, after which Gail effectively snubbed him. Strangely, Gail has not been seen since "Fit For Murder".
Cully Barnaby (later Dixon) (Laura Howard) (series 1-13)—Tom and Joyce's only child takes her first name from a village on Lake Geneva in Switzerland, where she was conceived during her parents' honeymoon. An inquisitive and bold young woman, she's inherited her parents' friendly attitudes and community spirit. Early in the series, she attended Cambridge University and dated a fellow drama student, called Nico. After that, she sometimes went out with and secretly flirted with DS Troy and DS Scott. She is an actress and frequently takes temporary jobs in the Midsomer area when "resting" between assignments. Like her mother, her tendency to do community work often leaves her personally involved with the murders that take place. She meets Simon Dixon (Sam Hazeldine) in "The Axeman Cometh", becomes engaged to him in "Death In A Chocolate Box" and marries him in "Blood Wedding". Laura Howard had far fewer appearances than her on-screen parents, but still appeared as Cully.
Other minor characters have also spanned their appearances across more than one episode. Solicitor James Jocelyne (Timothy Bateson) appeared in "Written in Blood", "Death's Shadow" and "Orchis Fatalis". Estate agent Olive Beauvoisin (Eileen Davies) appeared in "Death's Shadow", "Dead Man’s Eleven", and "Hidden Depths" (but in this particular episode she was credited as "Estate Agent"). Charles Jennings (Terence Corrigan) appeared in the same two episodes. David Whitely (Christopher Villiers) appeared in "The Killings at Badger's Drift" and "Death's Shadow". Causton's Mayor Dave Hicks (Brian Capron) appeared in "Shot at Dawn" and "The Sword Of Guillaume". Acting Chief Superintendent John Cotton (Nick Fletcher), appears in "Days of Misrule" and "The Dogleg Murders".
Many actors have made repeat appearances, but in different roles. In "Hidden Depths" John Lightbody is gardener Steve Hope, but in "Death and Dust" he plays the role of Jason Slater. Richard Hope appeared in "Judgement Day" as Gordon Brierly, the local veterinarian, and seven years later reappeared in the episode "They Seek Him Here" as local actor and historian Neville Hayward. Samantha Bond even starred in three episodes: "Destroying Angel" (2001) and "Shot at Dawn" (2008), and again in Neil Dudgeon's 2011 debut as lead character, being the episode "Death in the Slow Lane". Elizabeth Spriggs and Richard Cant appeared in the first ever episode, namely "The Killings at Badger's Drift", as mother and son Iris and Dennis Rainbird; they appeared again as Iris' sister Ursula Gooding and her son Alistair in "Dead Letters". Neil Dudgeon, the current Inspector Barnaby, appeared for the first time as Daniel Bolt , a character on the episode "Garden of Death" (2000).
Other featured roles include the assassinated Young Policeman played by Pablo Bubar (uncredited) in "Murder of Innocence" (2012).