The Bill
Series 21
Series 21 DVD cover
No. of episodes	106
Release
Original network	ITV
Original release	5 January (2005-01-05) – 29 December 2005 (2005-12-29)
Series chronology
← Previous Series 20 Next → Series 22
List of episodes

Series 21 of British television drama The Bill was broadcast from 5 January until 29 December 2005. The series consisted of 106 episodes, making it the series with the highest number of episodes in the show's final decade, tied with series 19. On 5 February 2014, the complete series was released on DVD in Australia as a Region 0, playable anywhere in the world.

The first half of series 21 remained a soap opera styled show, focused primarily on the personal lives of the characters with policing secondary at times, more so than recent years with big plots focused on the characters directly rather than their job, such as DC Jim Carver's bid to win back estranged wife Sergeant June Ackland, PC Honey Harman's romance with a murderer she met through a case and Inspector Gina Gold's battle with cancer. The series aired its second station fire in three years as racist PCSO Colin Fairfax staged a terrorist attack to shift blame onto the local Muslim community, the blaze resulting in the deaths of DC Ken Drummond, PC Andrea Dunbar and SRO Marilyn Chambers. The fire also served as the exit plot for pilot star Mark Wingett, DC Jim Carver controversially axed after 21 years. Following the death of his first wife Marie and later his best friend Ken in the station fire, Jim left Sun Hill after learning estranged wife June had begun an affair with experienced PC Roger Valentine. His exit led to three episodes in a single night, the fire aftermath followed up with a half-hour special focused on Jim and June that saw Jim decide to leave her behind to rebuild his life, the night's third episode part of the Uncovered spin-off series as it showed Jim's most memorable clips from his time on the show. Another spin-off, Uncovered: On the Front Line, was pulled before broadcast, but aired a year later in Australia.

Midway through the year, executive producer Paul Marquess resigned after three years in the role, replaced by sister series Murder Investigation Team exec Johnathan Young after the spin-off was cancelled. Young began plans to move the series away from soap and back into policing drama, swiftly writing out soap-style villain PC Gabriel Kent, whose actor Todd Carty had already announced he was quitting the show, in a plot that saw him commit suicide after being exposed for identity theft, murder, rape and a litany of other crimes. Young also brought an end to several Marquess era plots including Gina Gold's aforementioned battle with cancer and DC Terry Perkins' affair with his imprisoned brother's wife. However, he carried the plot surrounding Sergeant Dale Smith's affair with villain's wife Louise Larson (Rosie Marcel) into the next series. Young carried on the Marquess tradition of casting actors known for softer roles by introducing Birds of a Feather star Pauline Quirke as a child killer for one of his first plots. Young was also tasked with leading the show's second live episode, commemorating the 50th anniversary of ITV. The special episode showed a siege at Sun Hill in which several members of the relief were held hostage by a grieving father, seeking justice for his son's accidental death in a traffic collision. The episode saw a return for Gabriel Kent's alter ego to kickstart his exit plot but also brought back Cyril Nri as Superintendent Adam Okaro, whose time off-screen on break was preceded by the death of Okaro's wife and two children in a tragic car crash.

The station fire plot meant there were already several exits and new arrivals under Paul Marquess before his resignation, but he also axed Ciaran Griffiths after three years as DC Gary Best for a summer plot that saw him transfer after being shot on duty. Several recurring cast members were introduced by Marquess for personal plots tied to Sun Hill officers, but many of them were written out either before the year ended or early in 2006 by his successor Johnathan Young. Young introduced Hollyoaks and Footballers' Wives star Gary Lucy as PC Will Fletcher and brought back Chris Simmons as DC Mickey Webb after joining the series, but most of his cast work was to axe the fringe characters and non-police officers introduced by Marquess. He also ended a Marquess plot, the show's third serial killer storyline in as many years, by fatally writing out PC Lance Powell as the culprits were targeting gay men: it meant along with Gabriel Kent and the station fire victims, it was the second highest tally of police officer deaths in a series with 5, second only to the ten killed off in 2002. Bernie Nolan was the only character who left after Young took over that resigned, as she was intent on returning to her music career.