Has Batman v Superman finally revealed the secret identity of the Joker?

Have they gone? OK then, the idea is that the Joker is none other than... Batman’s sidekick Robin the Boy Wonder, turned mad during one of their adventures and determined to get back at his former partner.

This thought first arose a few months ago when fans noticed that puncture wounds on the Joker-graffiti-ed Robin costume displayed in Batman’s Batcave corresponded with scars on Jared Leto’s Joker himself, who’s set to appear later this year in baddie-themed movie Suicide Squad.

Immediately, fans began to wonder – could Robin, rather than having been killed by the Joker (as happened to Jason Todd, the second of Batman’s sidekicks in a 1988 comic) actually have BECOME the Joker? And could the “J” tattoo under Joker's eye (and the flash of feathers on his right arm) be a nod towards his past life as Robin?

After all, the Batman source comics have explored a similar idea before – in 2005, the murdered Jason Todd DID come back from the dead as an antihero with a connection to the Joker, though in that case he went by the identity of the Red Hood (a criminal identity previously used by the Joker before he went mad) rather than the Joker himself, and he wasn’t an out-and-out villain per se.

Perhaps the movie universe Robin was still beaten up by the Joker (explaining the wounds) and in his trauma took on his identity, maybe after Batman killed the original? Or maybe he’s the one and only Joker, having falling into the vat of chemicals traditionally associated with the character’s origin after being shot or otherwise injured in his Robin costume?

Now that Batman v Superman itself is here, redditors have spotted even more clues to indicate the plot twist. These range from the sight of Batman’s burned-out mansion (after all, who could infiltrate the security there but someone who knew it from the inside?) to the angry notes sent to the Dark Knight about letting his “family” die. The film reveals they were forged by Lex Luthor but some viewers believe they were originally intended to be from the Joker, before he was cut from the movie.

In particular, fans have focused on this line from Batman to Alfred when explaining his crusade against fellow hero Superman: “Twenty years in Gotham. How many good guys are left? How many stayed that way?”

Could it be that Batman’s experience of Robin turning against him to become the Joker made him suspicious of any other heroes, including Superman? And could this explain the apparent desperation he displays throughout the film, including the violation, several times over, of his comic book rule not to kill?

And, as the reddit posters point out, if this Batman kills people it seems odd that he’s let Joker live so long – unless he still has some small hope of bringing his old friend Jason back from the brink.

Sure, so far it’s all pretty circumstantial, but we can’t help but feel such a twist would fit perfectly in to the modern DC universe. For now, we’ll have to wait until Suicide Squad hits screens to see whether the joke’s actually on us.

Batman vs Superman: Dawn of Justice is in cinemas now