Doctor Who: The Pirate Planet (1978)

The Key To Time.

On the hunt for the second segment of the Key To Time, The Doctor and Romana try to land the TARDIS on the ice planet of Calufrax, only find find themselves on the planet Zanak instead.

Zanak, they discover, is a hollow planet that jumps through space swallowing up smaller planets and strip mining them of their resources, under the guidance of the half-human, cyborg Captain (Bruce Purchase).

The Pirate Planet was Douglas Adams' first Doctor Who script and fans of his seminal Hitchhiker's Guide to the Galaxy will certainly pick up resonances of his style and wit in much of the pithy dialogue, as he was working on that at the same time.

Zanak's design wouldn't have looked out of place in Magrathea's catalogue of designer planets (Magrathea was a hollow world in Hitchhiker's where other other planets were built).

However, there is even more afoot on the strange planet Zanak, with its growing psychic rebellion in the form of the Mentiads, the strange hold The Captain's nurse has over him and The Captain's own schemes - concealed behind his Brian Blessed-channelling bluster.

And on top of all that, The Doctor and Romana are having trouble pinning down the exact location of the second segment of the Key To Time.

Foreshadowing the production of Doctor Who moving to Wales by about 25 years, the location shooting for The Pirate Planet was conducted around a couple of villages in South Wales, in the Brecon Beacons and the caves of Dan Yr Ogof.

Tom Baker, sporting a nasty cut lip from an earlier accident, is on particularly manic form - no doubt empowered by Adams' way with words - and his fondness for Romana is clearly growing. It's just a shame that the resolution of this interestingly complex tale resorts to torrents of technobabble to tie up all its loose ends.