Star Wars fandom is agog at the suggestion that Luke Skywalker might turn to the Dark Side in The Last Jedi. This is all pure speculation at the moment. Sure, Mark Hamill has said "It's possible", but he was quick to add that "anything's possible". So what hints have there been that Luke might follow in the footsteps of his father?
"He has too much of his father in him"
In Star Wars: Episode IV - A New Hope, there's a telling exchange. "Luke's not just a farmer, Owen," says Aunt Beru. "He has too much of his father in him." "That's what I'm afraid of," replies Uncle Owen," gravely.
This throws up the question of how much they knew of Luke's parentage. More importantly, could this be an early hint that he is destined to embrace the dark side of the Force?
Luke's vision of himself as Darth Vader
On Dagobah in Star Wars: Episode V - The Empire Strikes Back, Yoda warns Luke about the dangers of succumbing to the Dark Side. To put him to the test, he's sent into a cave that is filled with Dark Side power. Here, he has a striking vision of himself as Darth Vader.
This foreshadows the later revelation about his real father, but also indicates how he susceptible is to the corrupting lure of the Dark Side.
Luke nearly kills Palpatine
Mark Hamill was reportedly very keen for Luke to go bad in Star Wars: Episode VI - Return of the Jedi. George Lucas was less enthusiastic, but this is certainly the episode in which we see the character flirting most dangerously with the Dark Side of the Force.
Along the way, he chokes Gamorrean guards and threatens Jabba the Hutt with death. Most tellingly, only the intervention of Darth Vader prevents him from slaying Emperor Palpatine.
Luke disarms Darth Vader
This is perhaps the turning point. During Luke's climactic lightsaber battle in Return of the Jedi, he draws on his hatred and anger to disarm Darth Vader.
This may be a temporary embrace of the Dark Side in extreme circumstances, and he pulls back from it once he sees Darth's severed hand. But we know that its power is addictive.
The Dark Empire comic-book
Now we should treat this with some caution as it's been declared 'non-canonical' by Disney, but the 1990s Dark Horse comic-book provides an intriguing potential storyline. It imagines Luke turning to the Dark Side as an apprentice of the resurrected Emperor Palpatine.
Star Wars: The Last Jedi lands at Cineworld on 15 December 2017.