If there's one thing you can say about Big Finish's 2013 release The Wrong Doctors, it's that it's not afraid to have fun with time travel within the classic series period of Doctor Who. In the new series we are used to seeing the Doctor overlap with his present timeline but in the classic series (and indeed during the Russell T Davies era of the show) it was something you absolutely couldn't do. Having the sixth Doctor meet the sixth Doctor is therefore a very novel idea by Matt Fitton. But does he manage pull off the story's potential?

Well, pretty much. There is a slight problem however in how it translates to the audio format. The Wrong Doctors takes place shortly after Trial of a Time Lord; the young sixth Doctor (Colin Baker) decides to drop the old Mel (Bonnie Langford) back home to wait for the old sixth Doctor who has already travelled with her to return. Meanwhile, the old-but-not-yet-old-enough-to-have-travelled-with-Mel Doctor (Colin Baker) arrives at Pease Pottage with the intention of picking up young Mel (Bonnie Langford) after losing his previous companion Evelyn Smythe. Both Doctors and both Mels are present in Pease Pottage at the same time and if the wrong Doctor were to meet the wrong Mel it could do considerable damage to the web of time. To add further complications, the village of Pease Pottage has been populated with people who have died years before...and some of them are even aware of their deaths, including Mrs Wilberforce (Patricia Leventon), who died in 1964 aged 80.

The Wrong Doctors does a brilliant job of mixing new series concepts with the classic series; this is a story that you could easily imagine Steven Moffat writing. I particularly love the idea of a village populated by dead people. It is a very intriguing one and made disturbing by how the characters who are aware of their deaths act so matter-of-fact about it. And then there's the chilling concept that the residents of Pease Pottage can only remember a day's worth of memories but act as though they have always known one another. Jedediah Thurwell (James Joyce) for example clearly fancies young Mel but their memories mean that they can't remember meeting one another beyond the present time.

Where the time travel falls apart is through the presence of both the young and old Doctors. Occasionally it is hard to follow which Doctor is with which Mel and it can feel like the story would have been better suited to the television format (especially when the old sixth Doctor is wearing his indigo coat - something that on television could have acted as a visual guide for the viewer). Some may require a flow chart when listening to this story; to his credit Matt Fitton tries to make the story easier to follow through nicknaming the two Mels 'Mel B and Mel C' but often it doesn't feel like enough. The two Mels barely interact anyway, aside from towards the end of the story where old Mel accidentally knocks her younger self cold.The old Doctor is also given the nickname of 'Indigo Jones' by old Mel (which is more useful than Mel B and Mel C) but I would have liked to have seen the young Doctor given a nickname too. Old Mel references Joseph and his Amazing Technicolour Dreamcoat in the story so why couldn't she have called him 'Joseph'?

None of the time travel confusion is either Colin Baker or Bonnie Langford's fault. Colin Baker and Bonnie Langford do a masterful job of making the young and old Doctors and Mels distinctive from one another. It's amazing how they manage to sound significantly younger when playing their younger selves, almost as though it actually is a younger Colin Baker and Bonnie Langford in the recording booth. Colin Baker's younger Doctor sounds much more bombastic compared to his older and wiser audio sixth Doctor. Bonnie Langford also manages to make younger Mel sound naive in comparison to her more experienced older Mel. This is Colin Baker and Bonnie Langford at their very best and I can't imagine there will ever be a sixth Doctor and Mel story where they both deliver a better performance than here.

It's especially impressive how much chemistry Colin Baker has with himself. Colin Baker and Colin Baker effortlessly bounce off each other with their multi-Doctor banter, helping to signify how much the sixth Doctor has changed from his TV adventures to his later audio stories. Many times it feels as though there are two Colin Bakers, like Colin Baker isn't just one person but made up of Colin Baker splinters spread throughout time. Who knows: maybe he fell down his own timestream and Nicholas Briggs failed to mention in the behind the scenes extra that there were two Colin Bakers recording the story? Or maybe Colin Baker exchanges banter with himself behind closed doors? Admittedly that sounds much weirder than Colin Baker splinters.

The supporting cast is also very strong, in particular Patricia Leventon as Wilberforce and James Joyce as Jedediah Thurwell. Both characters start off merely as caricatures - the sweet old lady and the confident young man of Pease Pottage - but their characters soon develop to become three-dimensional beings and are expertly brought to life by their actors. Both appear like characters from the sixth Doctor's era too; you could easily imagine Colin Baker's Doctor bumping into Wilberforce for example but I doubt she would have the amount of character development she gets here. The likelihood is that due to the poor quality of the writing she would have remained a caricature rather than becoming a layered supporting character. Wilberforce is a lady with a certain dedication to her: the kind of woman who will see things through to the end and who knows that one day everything must come to a stop. Jedediah on the other hand on the outside may appear confident but has a certain inner weakness that makes you question just how sure he is in the time-displaced society. At times it almost feels as though he subconsciously knows there's something not quite right.

Overall, The Wrong Doctors is a clever idea by Matt Fitton but occasionally the audio format is detrimental to the story's potential. It feels like a story that would work better as a televised episode of the show rather than as an audio drama. It is remarkable however how Colin Baker and Bonnie Langford manage to sound significantly younger when playing their younger selves. Both give outstanding performances as both their younger and older selves; Colin Baker in particular has a lot of chemistry with himself. The supporting cast is strong too, my favourite being Patricia Leventon as Wilberforce. Wilberforce may seem like a caricature at first but she soon develops into a fully-fleshed character; her steely dedication makes her a very interesting character to listen to. The Wrong Doctors is definitely worth the listen for Colin Baker's rapport with himself but it's the kind of story that requires one of Doc Brown's blackboard sketches to fully understan

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