Editing Silent Witness (section)

==Background==
The main character in the original series was based on Professor [[Helen Whitwell]], a forensic pathologist based in [[Sheffield]], whom McCrery had known while serving as a police officer. The programme followed the activities of [[Forensic pathology|pathologist]] Sam Ryan, played by [[Amanda Burton]], until she departed early in the eighth series.

There was a succession of regular supporting characters, changing almost every series, but Dr Leo Dalton ([[William Gaminara]]) and Dr Harry Cunningham ([[Tom Ward]]), who were introduced in the sixth series, continued as lead characters following Ryan's departure, with Dalton replacing her as professor.

A new character, Dr Nikki Alexander ([[Emilia Fox]]), was introduced in mid-series eight, based on [[Dr Brooke Magnanti]], a forensic scientist based in Sheffield. While working as a forensic anthropologist, she appropriates facilities and software in the pathology department to analyse an [[Iron Age]] find, with the belated, bemused and begrudging approval of Dalton. Dr Alexander is able to assist in a set of cases being investigated by the team, because it transpires that she has "worked in forensic pathology in [[Johannesburg]] for six months" and is certified by the Home Office to practice. She eventually overcomes Leo's reluctance and, with Harry's support, is offered and accepts a position on the team.

Before the 16th series begins, Harry has left to accept a position in New York City. He is succeeded by forensics expert Jack Hodgson ([[David Caves]]) and his assistant Clarissa Mullery ([[Liz Carr]]). At the climax of the 16th series, Leo is killed in an explosion. His replacement, Dr Thomas Chamberlain ([[Richard Lintern]]), is introduced at the start of the 17th series.

Although the show focuses heavily on areas of pathology, the police also have a presence in each case. During later series of the show, detectives and investigators tend to differ from episode to episode, with guest artists appearing in these roles. However, during the early years of the show several characters appeared regularly to investigate each case.

The first three series are set in [[Cambridge]]. The setting changed to London from the start of the fourth series, following Sam as she took up an academic position in the Lyell Centre, the Pathology Department of UCL. The programme remained in an academic setting until the end of series 16 when the Lyell appeared to have become separated from the university and operated as a stand-alone institution.

Each series is typically made up of a series of two-part stories. The first nine series generally featured eight episodes (four two-part stories), except that series 4 and 5 each featured just six episodes (three two-part stories); this was increased to ten episodes (five two-part stories) from the tenth series onwards, except series 12 and 15 which each featured 12 episodes (six two-part stories). The 25th series, broadcast in 2022, introduced a new format consisting of one story in six episodes,<ref name="WR"/> but the format reverted to five two-part stories from the 26th series onwards.

In 1998, the writer John Milne received an [[Edgar Award]] from the [[Mystery Writers of America]] for the second series episode "Blood, Sweat and Tears". In the United States the series airs during 'Mystery Monday' on [[BBC America]].