There have been several successive Action Force continuities, reflecting the ever changing nature of the Action Force toyline, the different companies producing (or reproducing) the fiction and the various different sources of material.
The Action Force comics are particular complicated and best divided into two - the Battle Action Force era and the Marvel UK era.
Battle Action Force
Action Force first appeared in comic form in the existing British war comic Battle (published by IPC Magazines) in 1983. When the strip proved successful the comic was renamed Battle Action Force and retained that title for four years until IPC lost the rights.
The Battle Action Force stories stand in their own continuity free from other sources, but can generate continuity confusion because they sought to explain the transition of the toyline from the UK originated local line involving Action Force fighting the Red Shadows led by Baron Ironblood to a renamed import of the G.I. Joe: A Real American Hero toyline, featuring Action Force fighting Cobra led by Cobra Commander.
Marvel UK secured the rights to Action Force in 1987 and over the next five years published a succession of titles containing both originated stories and reprints of the US G.I. Joe strips. During this period the toyline's name would change to first G.I. Joe the Action Force in late 1989 and then to G.I. Joe in 1991.
The initial Marvel UK title was the weekly Action Force which ran both UK originated and US reprinted stories. However US material reprinted started approximately two years into the life of the main G.I. Joe: A Real American Hero title and whilst the main reprints ran in sequence from issue #25 onwards, some stories were run out of sequence. This was particularly noticeable with reprints from the G.I. Joe: Special Missions series. Additionally the UK originated strips sought to interweave events with the US reprints, with the result that sometimes causes were changed.
The basic premise of Action Force at this stage was that it was an international organisation with several branches around the world. The European branch was based in London under the command of Flint who liaised with Trent from the Ministry of Defence. The American branch was under the command of Hawk, who liaised with officials from the Pentagon. Reference was also made to a branch in the Middle East under the command of Dusty. Members of Action Force based with any one branch would often be sent on assignments to work with another branch around the world.
An examples of changes was the printing of "Silent Interlude" approximately a year and half later than its place in the US continuity, with an additional UK originated prologue ("Consequences") and epilogue ("Truth"). The result was that the story was no longer the first encounter between Snake-Eyes and Storm Shadow since they joined their respective teams, whilst there was a different reason for Scarlett's capture and the epilogue was open about Storm Shadow's quest to find the killer of the Hard Master.
US reprints were also sometimes relettered to create a better flow of events. One such change came in the reprinting of "Twin Brothers" in issue #31. In the US this story saw the first appearance of Flint and Footloose, and Flint's first encounter with Lady Jaye. For the UK printing Footloose's name was changed to "Longslide" because the characterisation was very different to how he was handled in the UK strips. An entire page was relettered so that instead of introducing Flint it now established that Flint and Lady Jaye were on an assignment away from Europe.
Some of the reprints in annuals and specials were from significantly later in the timeline but made no attempt to explain alterations in the status quo or the sudden presence of characters who would later get a formal introduction in the regular comic.
The weekly Action Force ended after fifty issues (although annuals and the occasional special continued) and the two strands of strips went into separate titles. Reprints of the US material transferred to Marvel UK's Transformers title and in addition also appeared in the short-lived comic The Incredible Hulk Presents. For the first two years the strips continued to be relettered to change "G.I. Joe" to "Action Force" but otherwise no major changes to fit events with the UK originate continuity were made.
The UK originated strips ran in a new title, Action Force Monthly. This was also printed in the US as G.I. Joe: European Missions and an attempt was made to make the strips fit with contemporary US stories, largely through telling primarily stand alone tales. This detached the tales further from the US reprints in other titles. In addition issue #6 ran a special story entitled "As Thick as Thieves!" which served as a prelude to Action Force: The Movie but reflected the cartoon's status quo rather than the comics and better fits the former's continuity.
Throughout this period the annuals also ran, containing original text stories. These also contributed to confusion by often focusing on the actual toys on sale in the UK and reflecting their status quo rather than that of the comic stories being reprinted at the time. For example "Action of the Tiger!" in the G.I. Joe the Action Force Annual 1991 focused on the Tiger Force toyline. It also featured Storm Shadow as a regular Cobra agent at a time when he had long since defected.
In late 1989 Hasbro UK took the decision to rename the toyline to "G.I. Joe the Action Force". A special mini-comic entitled "Divided We Fall!" was produced by Marvel UK to explain the name change as being the result of a European team called "Action Force" and a separate American team called "G.I. Joe" merging. However all previous Marvel material had treated the two as branches of a single organisation called "Action Force". Furthermore the story depicts Cobra under the leadership of the battle-suited Cobra Commander (with no reference to his actual identity) containing Destro and Raptor, a status quo different from the regular strips.
The result of all this is that the Marvel UK Action Force continuity is especially complicated and at times seemingly incoherent when considered as a whole.
One other minor feature of the Marvel Action Force continuity are crossovers with other properties. Whereas most G.I. Joe crossovers take place in their own micro-continuity, separate from the relevant main series, nothing was ever said to indicate that the Action Force characters were not in the same universe as the other characters they encountered.
The story "Meditations in Red" established links with the mainstream Marvel Universe with the revelation that Quick Kick had been trained by Shang-Chi, the Master of Kung Fu, and also referenced others such as Iron Fist, Batroc and Elektra.
Later the story "Ancient Relics!" saw the team encounter the Transformers, in a story told in both Action Force and the Marvel UK Transformers comic. The story formed a key part of the Marvel UK Transformers continuity and was referenced there again several times (including Action Force's involvement), although Action Force were not shown encountering the robots again.
Although it is not known if the G.I. Joe: A Real American Hero cartoon was ever screened on British television, selected episodes were released on videotape, as was G.I. Joe: The Movie. The title was changed to Action Force: International Heroes and lines were redubbed to change the name of the team accordingly, also changing "Yo Joe!" to "Full Force!".
As noted above, issue #6 of Action Force Monthly ran a special story entitled "As Thick as Thieves!" which served as a prelude to Action Force: The Movie. This may be considered a part of the cartoon continuity rather than comics.
By the time the movie was released on DVD in the UK in 2003 the title "Action Force" had long been replaced by "G.I. Joe". However the first release of the movie had an error with the "Action Force" soundtrack used on the second half. In 2007 a correct release of the original US version was made.