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

Executive Producer Julie Gardner said "it was about giving David Tennant the biggest goodbye" - and Russell T Davies certainly delivers with an aspartame rush of a farewell two-parter.

It has the feeling of a spine-tingling epic straightaway: the sweeping cinematic shot of the lunar surface before zooming towards Earth and a clearly troubled Wilfred, all combined with ominous narration from Simon Skinner. In fact, the opening fifteen minutes are a marvellous microcosm of the Davies era.

The big Welshman blends moments of lightheartedness (the Doctor wearing a stetson and a lei whilst trying to make Ood Sigma laugh), with the grandiose resurrection of the Master, who nearly succeeds where Sauron failed in returning fully formed via a powerful ring. Nearly, because John Simm switches between the life force skull from Knightmare to full on Palpatine by firing lightning bolts from his hands. Either way, Simm is on fine frenetic form throughout.

So too is the wonderful Bernard Cribbins, minus the insane cackling and relentless turkey eating of course. Moreover, Euros Lyn said he "didn't really direct Bernard" in the Hesperus' gun turret as he happily "went off on one".

Tennant gives it everything in a bravura performance. Especially during his reflective moments with Wilfred that serve as the underlying catalyst to the devastating denouement: the sudden realisation etched on his face that it’s Wilfred who is knocking four times, which sees the Doctor react with intense and inconsolable rage.

Goodbye slim and foxy. Hello the chin: There’s no handy spare hand to stop the full transformation this time around in what is the most visually spectacular - and arguably most tear-jerking - regeneration in the show's history.