We all know the story, Doctor Who went on an unprecedented hiatus, and during that hiatus the Doctor returned in audio drama form. Except this happened twice, what that introduction most likely calls to mind are the Big Finish audio dramas we know and love today, but back in 1985 - during the 18 month hiatus - the BBC brought the Doctor and Peri to audio themselves for a one-off six-part adventure: Slipback.

Following a strange dream and an unexpected materialisation, the Doctor and Peri find themselves boarding the Vipod Mor, a ship captained by a being who is able to make his crew ill by the force of his own will, and operated by a computer with a mind of its own. As the Doctor investigates what brought them here, he gets separated from Peri, who finds herself tagging a long with a comedic duo of policemen.

Penned by then script editor Eric Saward, this is a surprisingly light-hearted and comical story, in stark contrast to the darker tone the TV series had been moving towards in then-recent years. Many of the writer's own stories such as Earthshock, Ressurrection of the Daleks and Revelation of the Daleks are themselves among the most notable examples of this increasingly dark direction, as well as Saward also acting as script editor for the show through that time. This change of direction works really well for Slipback, and suits the more bizarre nature of its side characters.

In line with the lighter tone, the Doctor and Peri's relationship is at its most amiable, with the usually expected moments of conflict between them being nowhere to be found. Colin Baker and Nicola Bryant are clearly both comfortable in their roles even moving into a new medium, both putting performances on par with what they were doing on TV at the time.

The ship's computer is the real star of the show however. Played by Jane Carr, it's a performance of two very distinct halves in quite a literal sense, portraying both the computer's bubbly outer voice, as well as the more serious inner voice, with its own agenda. The outer voice of the computer has so much personality and is a joy to listen to, able to bounce between various parts of the ship at a moment's notice allowing it to cross between various plot threads in a way other characters can't, both getting to have a wider variety of interactions and acting as a connective tissue between most elements of the story.

Another notable member of the cast is Valentyne Dyall, who previously portrayed the Black Guardian but is now playing the captain of the Vipod Mor: Captain Slarn. Dyall puts in a good performance, but his character doesn't get a chance to shine, feeling somewhat disconnected from the plot. Slarn never interacting with a character in any kind of opposition to him doesn't do him any favours either, while he still has a role to play it's all tangential and leaves a feeling of lost potential. It's an interesting and less traditional approach but doesn't quite pay off.

The format of the story is also very non-traditional, with each of its six parts only running for ten minutes each. The shorter episodes make the story's progression feel much more incremental, having such little time to develop its characters and move things along. Listening to them in isolation rather than as a complete package doesn't come recommended.

The ending is unfortunately a deeply unsatisfying anti-climax. Without giving too much away, it seems to end rather abruptly, with very little agency from our leading duo. The ending does at least come about in an interesting way, and has a particularly nice moment for one of the side characters.

Slipback is an imaginative piece and a fun listen. You're not getting the most fleshed out plot, owed both to the way it segments off its characters and the shorter per-episode runtime, but you are getting an interesting and entertaining cast of characters and the unique novelty of an audio drama made during the classic series and during its leads' on-screen tenure. It has enough going for it that - to this reviewer - the story has earned its place among the sixth Doctor's televised adventures in future re-watches.

It's a shame that no further audio stories were produced at the time, there truly is a surreal factor to hearing Baker and Bryant in the format as they were in the 80s and it would have been interesting to see what kind of stories would've followed and where they would take the series tonally. Doubtlessly, further audio stories would've helped tide fans over through the rest of the hiatus, still having over a year to wait for the show to return after Slipback concluded. It's an interesting thing to think about, but perhaps in the alternate version of history where Slipback led to many more audio dramas, Big Finish wouldn't have emerged at the tail end of the century, and with the Sixth Doctor and Peri still adventuring together over 40 years later through them, that's not something to wish away.

If this review has sparked your interest, Slipback is available on CD and the third disc of the Season 22 Blu-ray set.