Vigil returned to BBC One on Sunday night for series two, which sees Suranne Jones and Rose Leslie reprise their roles as Amy Silva and Kirsten Longacre, who are drawn into the dangerous world of drone warfare.
While viewers have praised the gripping new episodes, some eagle-eyed fans have been quick to point out the inaccuracies, especially the incorrect badges on military uniforms.
One person wrote: "Hopefully #Vigil will improve but as a Royal Air Force Veteran I resent the unforgivable inaccuracies, e.g. dropping Royal off the name incorrect cap badges, failures in dress code, just to list a few. It had the potential to be a gripping drama but so far it's pants."
A second person penned: "Just started watching #Vigil series 2 on @BBCiPlayer. Two minutes in, I find myself frustrated that once again, a mainstream TV company still [hasn't] hired decent #military advisors regarding uniform, rank & insignia. Don't get me started on the rest."
A third viewer commented: "#BBC on #Vigil proving that they can not only get naval uniforms and rank insignia wrong in series 1 they can also get it completely wrong for the RAF in series 2 as well! Perhaps it's done on purpose to show us it's supposed to be a comedy?" while another added: "Just watched the first few episodes of #Vigil. Seems like a good story but can't concentrate because the berets, cap badges, rank slides, uniform & basically everything about the 'British' Air Force is stressing me out.
What viewers may not know, however, is that the uniform inaccuracies are intentional.
While speaking at a Q&A event at the BFI in London ahead of the release of series two, creator Tom Edge and executive producer Jake Lushington explained the reason behind the costume errors in series one and two.
When asked if they did much research into military practice whilst creating series two, Tom told HELLO! and other press: "On both seasons of the show we've been lucky to have really good experts, people who've done the roles and who've served, for instance, in some places in the Middle East as part of RAF joint ventures. We take that seriously. Sometimes, we get pushback, 'Oh, you've got the buttons wrong,' but we actually have to get the buttons wrong for the copyright."
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Jake added: "If you really look at the signates, it says British Air Force, rather than Royal Air Force.
"Because we are a drama, we fictionalise intentionally and sometimes people think that's a mistake but we've done that so the audience can have some point of difference from a documentary. But beyond that, we try and do as much research as possible and sometimes they won't be able to tell us things but we can ask if we're right or not."
Vigil continues on Tuesday 12 December on BBC One and iPlayer at 9pm.