Actor-Inspired Element: The characters of Cowley, Bodie and Doyle were changed substantially from their original concepts. Cowley was only intended to be 'Northern' not Scottish like Gordon Jackson. Lewis Collins managed to tone down the formal nature of Bodie's costume by series two. Doyle had the biggest change as he was intended to be blond-haired, blue-eyed and be-suited. Martin Shaw was cast (and suggested to cut his brown permed hair) and argued that Doyle wouldn't wear suits and instead turned up to the first day of shooting wearing jeans and a T-shirt, despite being told that he'd be sent home by the previous director if he did.
Actor-Shared Background: During the show's run, while playing a former paratrooper, Lewis Collins became a paratrooper himselfnote as a member of the Territorial Army, the predecessor to the current British Army Reserve. He later made a serious attempt at joining the the Territorial SAS and passed the initial entrance tests but was rejected before Selection began when it was deemed that his fame made him a liability.
Alan Smithee: P.J. Hammond wrote the fifth episode "Heroes" under the pseudonym James McAteer. He asked for his name to be removed from the credits because he wanted to dissociate himself from certain changes that were made to his script by other people.
Banned Episode: In the episode "Klansmen" was banned in Britain for many years due to its violence and racist content (never mind this Very Special Episode has an anti-racism theme), but is available on DVD or streaming services.
Blooper: Loads of continuity errors due to productions running over schedule, meaning that scenes were often shot weeks apart. And there's the scene from "Blind Run" where Martin Shaw jumps into the back of a van, only to go flying out the back again when the van drives off.
Cast the Runner-Up: Lewis Collins revealed that he auditioned at Pinewood Studios for a minor role on the show, as a military sergeant, when the casting agent thought he might be a good replacement for Anthony Andrews and recommended him to the producers.
Corpsing: In the scene where B&D meet with arms dealer Marty in "Hunter/Hunted", the actors are repeatedly smirking as if something funny is happening off-screen.
In 2004 plans were being drawn up for a film version with Lewis Collins approached to play Cowley, but after negotiations broke down the film was abandoned.
In 2011, film company Lionsgate announced it had acquired the rights to series and intended to begin shooting a movie in 2011. The characters of Bodie, Doyle and Cowley would be played by new actors. The film would have been a prequel to the series concerning how Bodie and Doyle entered CI5.
Distanced from Current Events: In 1987, ITV was re-running some episodes. After the Hungerford shooting incident the particular episode that was to be aired, "Lawson's Last Stand", had a theme that was deemed insensitive and was replaced by the less violent "The Untouchables".
Hostility on the Set: Deliberately invoked, at least initially, by the creator — the two leads were cast because they did not get on while working together on a previous project and he thought that would give the onscreen relationship between them the edge he wanted. While they worked out their differences in fairly short order and became friends offscreen they were good enough actors to keep the onscreen dynamic he wanted.
Missing Episode: "Klansmen" has to this day never been shown on British terrestrial television, and only once on cable television in 1997 (in a bizarre aversion of the No Export for You trope, it has been shown in other countries).
Money, Dear Boy: Martin Shaw remarked that at the time he was offered the role of Ray Doyle, he only accepted because there weren't many other offers of work.
Old Shame: Martin Shaw (who played Doyle) blocked re-runs for years, only relenting after the death of Gordon Jackson (Cowley) so his widow could benefit.
One for the Money; One for the Art: According to casting director Esta Charkham, Pierce Brosnan took a minor role in "Blood Sports" just so he could earn enough money to pay the fare to fly to the US, where he had been offered a role in a Mini Series called The Manions of America.
The Other Marty: Anthony Andrews was originally cast as Bodie. He had already completed three days filming when he was replaced.
Out of Order: The third episode, "Old Dog with New Tricks", was meant to be the pilot, (and therefore is a proper introduction to CI5 and its purpose) but "Private Madness, Public Danger" aired first, probably because it has a better Establishing Character Moment for Bodie and Doyle. "Old Dog with New Tricks" just has them slouching into a corridor after Cowley yells for them. "Private Madness, Public Danger" has them shooting cans off a wall, then engaging in Witty Banter when Cowley gives them their assignment.
Much of the laddish banter between Bodie and Doyle was improvised on-set by Collins and Shaw in order to entertain the crew, notably their conversation about Cowley in the Capri during "Look After Annie". However, these conversations proved to be so popular, that the editors left them in the finished versions, and they came to be regarded by many viewers as some of their favorite parts of the show.
During the filming of a car chase in "Everest Was Also Conquered" a tire blew out, so they decided to have the Villain of the Week end the chase by shooting out a tire on Bodie and Doyle's car.
In "Blind Run", Collins was crossing a plank between two buildings which slipped out from under him, adding to the drama if not the production's Health & Safety compliance. The blooper where Shaw falls out the back of a van as it accelerates away was left out however (but not the scene where Shaw hits his head as he does a dramatic leap from the canal bank onto a boat).
In "Rogue", Collins drops his gun on the floor while putting on his shoulder holster. Shaw improvs the disapproving: "Shot your foot off" line.
Jon Finch turned down the role of Doyle, claiming that he "couldn't possibly play a policeman".
Bodie was supposed to return in CI5: The New Professionals as the mentor to the new team, as Lewis Collins had re-located to America and the show had American funding, but Collins turned it down.
Career Resurrection: Richard Brooks was looking for a more modestly priced production, at $6 million, in the wake of the $10 million spent on Lord Jim, a financial and critical failure for Brooks that had come out a year earlier. The film was a big hit and led to a comeback of sorts for Brooks.
Cast the Expert: Lee Marvin, a former Marine, took it upon himself to keep the film's guns clean in the unpredictable desert conditions.
Development Hell: Plans for a remake were announced in 2000 but as of 2011 haven't been followed through. Among the people attached were screenwriter Bruce Feirstein and John Woo.
Burt Lancaster and Lee Marvin did not get along during filming due to Marvin's alcoholism, which was making him unreliable and difficult at the time, infuriating Lancaster. Director Richard Brooks felt the need to intervene because he feared Lancaster was going to "take Lee Marvin by the ass and throw him off that mountain."
According to Marvin's widow, a disagreement arose between Marvin and Lancaster about the authenticity of the weapons. Burt could not care less, and Lee was well-known throughout his career for insisting on accuracy with guns and costumes. A big blow-up ensued. Brooks implored Lee to make peace with Burt, who was known to possess a rather inflated ego. Lee did so on his knees before Lancaster, wailing for forgiveness. It is unknown if Burt saw that Marvin was mocking him.
No Stunt Double: Despite the principal male actors being in their fifties (except for Lee Marvin, who was only 42), all of them insisted on performing their own stunts. However, only Woody Strode performed all of his stunts as there were no black stuntmen who came close to his height and stature. Burt Lancaster, who was 52 at the time, did most of his own stunts, including being hung upside down in Coyote Pass and running across the top of the moving train car. The studio balked, however, at Lancaster climbing the side of the cliff in the pass to plant the dynamite and a stuntman was substituted.
On-Set Injury: During the filming of the scene where Maria attempts to escape through a canyon wired with dynamite, Claudia Cardinale's stunt double was badly injured during the explosion. Cardinale, who had never ridden a horse before, performed the stunt herself for the final cut, and escaped uninjured.
Stillborn Franchise: The success of the movie led to calls from the studio for a sequel, but only with the four principals actors involved because of the fiasco surrounding the sequel to The Magnificent Seven (1960), where only Yul Brynner returned. However, all of the principals had full filming schedules. By the time any space could be cleared, Robert Ryan's health (due to lung cancer) made it impossible for him to perform the physical work necessary for the movie. After his death in 1973, all plans for a sequel were scrapped.
Stunt Double: Even though Jack Palance was as tall as Woody Strode, he had to use a stunt double for the scenes where he was wounded and fell off his horse, because falling the wrong way off a horse could lead to serious injuries.
