Warning: Contains spoilers for Peaky Blinders season 6, episode 1.

While Peaky Blinders is partially ahistorical, season 6 is setting itself up to face the same history problem caused by the Peaky Blinders season 5 villain. Peaky Blinders season 6 sees the series jump forward in time another few years to 1933 and the end of prohibition. While Tommy Shelby might be trying to retire, his final job is set to repeat a history mistake for Peaky Blinders.

Peaky Blinders has always included representations of historical figures. In Peaky Blinders season 1, Winston Churchill was introduced and he has reappeared at various key moments throughout the series. In Peaky Blinders season 5, Tommy Shelby (Cillian Murphy) has entered the world of politics and is introduced to Oswald Mosley (Sam Claflin). Hoping to prevent the rise of fascism in Britain, Tommy plots to assassinate Mosley and is encouraged by Churchill himself. However, in the Peaky Blinders season 5 finale, the plan is foiled by the IRA.

Related: Peaky Blinders Soundtrack Guide: Every Song In Season 6 (So Far)

The Oswald Mosley plot caused a problem for Peaky Blinders season 5 as he was cast as the main villain and Tommy Shelby’s plan to kill him could never succeed. Mosley’s history preordained his storyline: he formed the British Union of Fascists in 1932 and was eventually jailed in 1940, but he was never assassinated. If Tommy’s plan had been successful, it would have taken Peaky Blinders from bending history a bit to completely altering the course of British history in the run-up to World War II. Peaky Blinders season 6 is doomed to have its plot defined by established history once again. Mosley presumably remains as a threat in Peaky Blinders season 6, and the newly introduced character Jack Nelson (James Frecheville) is based heavily on Joseph Kennedy Sr. who, like Mosley, lived much longer than the projected end of the main Peaky Blinders storyline. All of this means that Tommy Shelby’s machinations are ultimately doomed to failure, even outside of his own fatalism.

Oswald Mosley

Peaky Blinders has certainly been content to be ahistorical in certain ways in the past. Most notably this relates to the Peaky Blinders themselves. While the Peaky Blinders existed as a gang, they largely lost control as a force in Birmingham by 1910 and were entirely eradicated by the 1920s. Billy Kimber, whose gang overtook the Peaky Blinders, is the season 1 villain and was killed, allowing the Peaky Blinders to rise to power rather than die out. However, while the show allowed this historical inaccuracy and others, they have tended to e small details that related to the gang themselves. Killing Oswald Mosley or the Joseph Kennedy Sr. stand-in would have much bigger impacts on the larger timeline, as Kennedy went on to influence the political careers of his sons and helped JFK to be elected president.

Of course, there is precedent in TV and movies for completely throwing the real historical timeline out of the window. Famously, Quentin Tarantino’s Inglorious Basterds saw a finale where the heroes killed Adolf Hitler in 1941. However, while diverting the timeline like this for the Peaky Blinders season 6 finale or movie might be a dramatic way to end Tommy Shelby’s story, it would cause a knock-on problem. There are several potential Peaky Blinders spin-offs in the works and if they were to take place later in the timeline then the original series antics could cause huge history problems for them.

Next: Peaky Blinders: What Gypsy Phrase "Tikna Mora O Beng" & Ruby's Vision Mean

Peaky Blinders releases new episodes Sunday on BBC.