10 Important Doctor Who Details That Are Almost Never Mentioned

Heaven Sent earned itself a place on the list of all-time great Doctor Who episodes as soon as it was broadcast. Peter Capaldi's epic solo performance blew everybody away, and the mind-bending story of the Doctor endlessly reliving the same events inside his confession dial for billions of years might just be Steven Moffat's finest hour as a writer.

But this story also has some interesting implications for the show, which have never been properly explored: the original Doctor is dead.

Most “time loop” stories simply have everything magically reset at the end of each loop. No matter what happens to the characters, we always know they’ll be fine once whatever timey-wimey shenanigans are going on have put everything back in place. But that’s not what happens in Heaven Sent. Here, the current version of the Doctor dies, using their body as fuel to power the teleporter so it can output another version of the Doctor.

As the Doctor himself puts it, he's “burning the old me to make a new one.”

We’re not looking to kick-off a debate about whether or not teleporters are actually murder-boxes (we’ll leave that one for the Star Trek fans), but in this instance, the teleporter can’t be simply rematerializing the Doctor out of the same atoms that were initially dematerialised, because we see the current Doctor dying as the new one is made.

Even Moffat has sort-of confirmed this theory, cheekily responding that "[the Doctor] first teleported in The Keys of Marinus – he's been a copy since then – deal with it."

In other words, the Doctor who originally stole a magic box and ran away is no more. Since Heaven Sent, we’ve actually been watching the adventures of the Doctor’s teleporter clone number 3,000,000.