DS Burnside reappears twice more in the episodes "Ringer" and "The Chief Superintendent's Party". By this time, his apparent villainy is an open secret at the station, and few are pleased to see him, least of all Sgt Cryer and DI Galloway. However, DS Burnside is indifferent to their hostility, and sets his sights on WPC June Ackland. Burnside is too thick-skinned to sense her obvious repulsion towards him, and June takes great delight in stringing him along. However, other Sun Hill officers take exception to his pursuit of her, prompting DC Mike Dashwood to intervene. He informs Burnside that June is Galloway's mistress, forcing the rogue detective to switch his sights elsewhere.
He was called "Tommy" when in series one and two, but when he appeared as a regular character from 1988 onward his first name was changed to "Frank" as there was a real-life "Tommy Burnside" serving in the Metropolitan Police at the time.
By 1988, The Bill had switched to a twice-weekly half-hour format, with significant cast changes. Galloway's departure from the series creates a vacancy for a new DI, and the first half-hour episode, "Light Duties", sees officers taking bets on who the new incumbent will be. DS Ted Roach has his own sights set on the job, and is appalled to learn that DS Burnside is a rival candidate. When Burnside takes the post in the episode "Just Call Me Guv'nor", DS Roach and Sgt Cryer are outspoken in their views on the appointment of an apparently corrupt officer.
It soon becomes clear that DI Frank Burnside is far removed from his previous incarnation. Besides a new rank and Christian name, Burnside acquires a new outlook. The sneering wide-boy of the hour-long shows is replaced with a darker and more authoritative character. His apparent corruption is explained away by Inspector Christine Frazer as a result of Burnside having worked undercover on Operation Countryman, forcing Sgt Bob Cryer to swallow his pride and welcome DI Burnside to Sun Hill. However, DS Ted Roach is far harder to win round.
Despite their similarities, both having maverick tendencies, but ultimately on the right side of the law, DI Burnside and DS Roach have an uneasy working relationship. Roach's increasing bitterness at having been passed over for promotion, coupled with a thinly-disguised drink problem, make him almost unmanageable for his senior officers. When matched with DI Burnside's explosive personality, the two officers physically come to blows. However, their similar policing styles and views lead to them developing a mutual respect. As the police force becomes more politically correct, maverick officers such as DI Burnside and DS Roach are increasingly seen as a dying breed. As such, their working relationship becomes one of mutual dependency, each watching the other's back when either of them sail too close to the wind. When DS Roach walks out of the job following an assault on Inspector Monroe, DCI Jack Meadows caustically remarks that it is "the end of an era for DI Frank Burnside."
Meadows' prophecy is proven right later when DI Burnside mysteriously fails to show for work. It is explained that Burnside has been taken out on a "special operation", prompting his colleagues to speculate that he is working undercover. As the years go by, a succession of DIs take Burnside's office.
In 1998, The Bill returned to the hour-long format. In October of that year, DI Burnside returned to the series in a two-part story, "Cast No Shadow" and "Betrayal". The story follows an investigation led by DS John Boulton and DC Jim Carver into a protection racket, which leads them to Manchester. Carver is shocked to discover that his former boss is one of the main players in the operation, and he and Boulton are forced to take DI Burnside back to Sun Hill in handcuffs. Meadows is openly hostile towards his former colleague but, reminiscent of Sgt Bob Cryer ten years earlier, he is forced to backtrack when it emerges that DI Burnside is working undercover. Furthermore, Burnside had been promoted to the rank of DCI within the field, and is now on an equal footing with Meadows.
DCI Burnside then appears semi-regularly in The Bill. He is now head of the elite Crime Operational Command Unit, and his work frequently brings him into contact with Sun Hill officers, investigating high profile cases. One such investigation leads to him arresting DC Jim Carver on suspicion of murder. Despite their rocky start, DCI Burnside took the impressionable young DC Carver under his wing during his reign as DI, and is sorry to see his friend's sad fall from grace. Carver begins drinking heavily following his enforced move back to uniform, marking a steep decline into alcoholism. When he wakes from a drunken stupor to find a murdered prostitute beside him, it seems Carver's career is over. However, DCI Burnside manages to solve the murder, and urges Carver to seek help for his addiction.
DCI Burnside is the principal character in the episodes in which he appears, and the popularity of these episodes paved the way for a spin-off series, Burnside. The six-part series, three consecutive two-part stories, follows Burnside's new role as a DCI with the National Crime Squad, described in the show's publicity as the English equivalent of the FBI. The series is much grittier than The Bill, as its post-watershed timeslot enabled stronger language and more violent scenes. Although each two-part story focuses on a different crime, the series is underpinned by a story arc, which explores DCI Burnside's pursuit of gangland boss Ronnie Buchan. Buchan had murdered Burnside's best friend years earlier, and Burnside is determined to use his newfound influence as head of a team within the NCS to bring Buchan to justice. The series ended with Burnside vowing to nail Buchan by whatever means necessary.
Despite the popularity of DCI Burnside's character in The Bill, his spin-off failed to take off, and was axed after just one series