The Lead Police Detective is a plain clothes police officer who serves as the chief investigator and (often) protagonist of the story. They report to Da Chief, but have, at minimum, one subordinate (in many television series, this is a younger partner) who often acts as The Watson for them. This character has just enough rank to order people around, and not enough to justify spending all their time in HQ. Instead of sitting in at his desk directing entire units, he will be out and about investigating crime scenes and interviewing witnesses himself.
In Long-Runners, the character may be promoted to Da Chief or retire, prompting their partner (or a completely new character) to replace their role as Inspector. Both the Inspector and Da Chief can be compared to The Captain, the military equivalent. Depending on the story, the Lead Police Detective may have a large team of subordinates who are there primarily to show they have rank.
- The Jules Verne thriller Master of the World stars John Strock, a police detective traveling around America on the track of a mysterious Mad Scientist. We also get to meet Strock's boss Mr. Ward, as well as several subordinate agents who act as Watsons.
- The Nursery Crime series features DCI Jack Spratt, with Sergeant Mary Mary as his main assistant, and team of subordinates named Butcher, Baker and Kandlstyck-Maeker.
- In Foyle's War, Detective Chief Superintendent Christopher Foyle has a higher rank than usual but still investigates his cases in person, due to being in a small town and having a manpower shortage on account of the War. He is assisted by Sergeant Paul Milner (invalided out) and MTC driver Sam Stewart (female).
- Inspector Morse: Chief Inspector Morse, with his partner Sergeant Robert Lewis. After the series ended, Lewis was promoted to Lead Police Detective in Lewis.
- Midsomer Murders: DCI Tom Barnaby, with a succession of assistants. At the end of the thirteenth season, Barnaby retired, and was succeeded by a new character, DCI John Barnaby, his cousin.
- In Pie in the Sky, Detective Inspector Henry Crabbe is the protagonist. He investigates with the assistance of WPC Sophia Cambridge (who levels up to Detective Sergeant by the end of the series) and later PC Ed Guthrie and WPC Jane Morton.
- Taggart: Detective Chief Inspector Jim Taggart, assisted by Detective Sergeant Peter Livingstone and then Detective Sergeant Mike Jardine. Following the death of Taggart's actor, Jardine was promoted to Lead Police Detective and gained a sidekick of his own.
- Detective Inspector Thomas "Tommy" Lynley of The Inspector Lynley Mysteries, who forms an Odd Couple crime-fighting duo with his partner Detective Sergeant Barbara Havers. In a break from the formula, however, if she's younger than him, it's not by muchnote , and the show is as much about her as it is about him.
- Played with somewhat in Hill Street Blues: Individual episodes usually followed a Two Lines, No Waiting structure, but whenever there was a multi-episode story arc about a lengthy investigation then one of the cast would be elevated to this trope during scenes involving the A-plot. It was most noticeable when Belker or Goldblum got the gig, but even when partners La Rue and Washington were jointly assigned to the case, one of them would have a slightly bigger role than the other.