The Doctor meets old friends – and old enemies. But which is which – and who is Who? One thing is sure: they all have a story to tell… 

The Sixth Doctor (Colin Baker) and his companion Mrs Constance Clarke (Miranda Raison) are set to return in May 2025 for three fabulous audio drama adventures across time and space. 

And there’s a very special reunion in store, as the TARDIS crew crosses paths with Iris Wildthyme (Katy Manning) – the eccentric ‘transtemporal adventuress’ who travels the multiverse in her double-decker bus. 

The Key to Many Worlds, a story written by Iris’s creator Paul Magrs, begins with the Doctor and Constance arriving in thirteenth-century Baghdad, where they meet an ageing Marco Polo (Terry Molloy, best known to Doctor Who fans as Davros). 

His adventures at an end, the legendary traveler has been tasked with transporting a certain enchantress back to Venice. But Iris Wildthyme doesn’t take well to being kept prisoner, and so performs her greatest trick yet – she swaps bodies with the Doctor! 

The explosive reunion is a long time coming; Katy Manning’s Iris has previously appeared alongside Colin Baker’s Doctor only once, in the 2003 Doctor Who audio drama, The Wormery. This time, the Doctor has his work cut out – not only does he have to deal with Iris, he has to be her… 

Writer Paul Magrs said: “The Key to Many Worlds was a great chance to reunite two great voices – Katy and Colin – from The Wormery all those years ago, and to twine them not only in one of my favourite Doctor Who genres, the historical saga, but also in one of my favourite science-fiction tropes, the mind-swap.” 

Colin Baker added: “Upon reading this script, my first reaction was, oh, good, another one that's good and clever and touching and rather exciting. Things get turned on their head!” 

And, Katy Manning said: “It's been an absolutely joyous day and I actually climbed into the skin of Colin Baker! I’ve got grin-ache! We’re so lucky, Paul Magrs is a wonderful writer.” 

Doctor Who – The Sixth Doctor Adventures: The Cosmos and Mrs Clarke is available to pre-order now for just £24.99 (collector’s edition CD box set + download) or £19.99 (download only). The collector’s edition CD box set is strictly limited to 1500 copies and will not be repressed. 

The three audacious new adventures for Ol’ Sixie are: 

The Story Demon by Julian Richards 
The Key to Many Worlds by Paul Magrs 
Inconstancy by Ian Potter

A second Sixth Doctor Adventures box set (Title TBC) will follow later in 2025. Both can be pre-ordered together in a bundle for just £47 (collector’s edition CD box set + download) or £38 (download only). 

Alternatively, listeners can buy this series as part of a bundle of all 15 Classic Doctor Who box sets released in 2025 for £335 (collector’s edition CD box set + download) or £275 (download only).   

All the above prices (including pre-order and multibuy bundle discounts) are fixed for a limited time only and guaranteed no later than 31 January 2025.

Please note that Big Finish is currently operating a digital-first release schedule. The mail-out of collector’s edition CDs may be delayed due to factors beyond our control, but all purchases of this release unlock a digital copy that can be immediately downloaded or played on the Big Finish app from the release date.