Doctor Who: Every Post-Regeneration Episode Ranked Worst To Best

There's an ethereal feeling to the TARDIS's Zero Room, with Its infinite corridors, and how the Doctor's new crickety cricket outfit is readily displayed that's akin to the 2001: A Space Odyssey neoclassical bedroom.

We're used to - especially in the modern series - the post-regeneration episode representing a completely fresh start. But Castrovalva is pretty much a continuation from Logopolis in many ways: that overall ethereally measured tone at odds with the epically imaginative danger of the TARDIS hurtling towards the Big Bang itself; the Master manically laughing - well, you would to, trapping Adric in a sort of Crystal Maze spider's web.

Oh, and those good old block transfer computations. No wonder the cloister bell was sounding to give them some much-needed urgency.

Though it's partly due to his difficult regeneration, Peter Davison does bring that welcome shot of adrenaline after Tom Baker's moribund turn in Logopolis. This, in some ways, made it easier for Davison to follow in the doyen of Doctor Who's shoes.

Still, just enjoy the bizarreness as Nyssa and Tegan push the Doctor in his IKEA restorative cabinet atop his electric wheelchair, which comically flares up like a random Simpsons explosion as it rolls down into the river.

It would be really interesting and awesome to see these story ideas from Christopher H. Bidmead - the Master's "installed a trap behind that trap" de-ception - developed for the modern series, especially with visual effects now provided by the gorgeously cinematic DNEG.