Doctor Who: The Doctor's Regeneration Episodes Ranked Worst To Best

The 2017 Christmas special is a pleasing palette cleanser following the epic series 10 finale.

It was a neat idea by Steven Moffat to intertwine the Twelfth Doctor's swansong with his past incarnation's final story, The Tenth Planet, as it created a fitting link to a seminal part of Doctor Who Lore, whilst also retroactively explaining the First Doctor's extended absence within that serial's narrative framework.

Moffat opts for a more restrained and introspective exit for both himself and Capaldi, with subtle references from his showrunning era throughout: a final, touching nod towards the Lethbridge-Stewart family, the mention of Villengard connects, albeit tenuously, to Moffat's very first story he wrote, The Empty Child/The Doctor Dances - merely a geek spot but it brings a smile to the face.

Despite the less is more feel to the episode, the Twelfth Doctor's personal mission in helping his former self come to terms with regeneration is epic in itself: if the First Doctor doesn't change then, never mind ripples, that would create a Van Cassadyne energy of catastrophic proportions across all of time and space! Fortunately, us Whovians have a TARDIS blue diary at the ready just in case we need to bring the Doctor back.

What makes the Twelfth Doctor's farewell roll call to companions past incredibly sad is when he says: "You're not even really here. You're just memories held in glass."

Goodbye attack eyebrows. Hello brilliant new era: Capaldi lets go with poise and great dignity and passes on the sonic screwdriver with sage advice - which we should all heed - to Jodie Whittaker's Doctor.