Flip Flop is a curious beast. Famed for the extraordinary device of having two discs which can be listened to in either order, it arouses strong feelings on both sides of the discussion over whether such gimmick stories are acceptable or not. Some people like nice, clear, linear stories in which Something happens, the Doctor arrives, he and/or his companion(s) are placed in mortal danger on three separate occasions, there is a last second scramble and everyone lives happily ever after. Other people relish innovation as people, places, structures and styles are played with to create something we’ve not seen or heard before. Witness the huge divergence of opinion over the recent "Love and Monsters". Generally speaking, innovative stories tend to be remembered for the innovation which makes them innovative. Flip Flop came at the end of a four-story run of unusual releases. Doctor Who and the Pirates saw a musical episode (as well as much entertainment derived from the unreliable narrator premise), Creatures of Beauty was a story told in an apparently random order with scenes shuffled up and dealt to the audience by Nick Briggs, Project Lazarus was told as two two-part stories with two different Doctors, and Flip Flop rounded off the quartet with a figure of eight story (or at least that is the best shape I can come up with) that has no beginning or end.

Although it can be listened to in either order, I personally think it works best with the Doctor and Mel arriving in the Puxatornee dominated by the Slithergees, going back in time and witnessing the death of the President and retuning to the post-war wasteland of the alternative Puxatornee. Although both versions are horrible places in 3090, the radioactive slums works best as the "worse" version necessitated by the story. It is a world without any hope (and indeed is destroyed half way through the disc) while the Slithergee world at least has a few dying embers of possibility. At least that is how I look at it having just listened to it that way around. Maybe the other route instils a sense that they are better off dead than reduced to miserable slaves.

But the most interesting thing I got out of Flip Flop was the way the unique story structure diverts your attention away from just how cutting the story is. One "half" of the previous thirty years of Puxatornee’s history reads very much like a Daily Mail reader’s version of the last thirty years of Britain’s – immigrants arrive in search of a better, safer life. Through manipulation of weak, liberal politicians and implied threats of violence, they gain and ever greater foothold until they receive preferential treatment in important areas of life. They demand representation on local political bodies while keeping their own committees exclusive to their own kind, they start claiming to take offence at the local customs until those customs are worn away, they even get Christmas erased from the calendar because it is insulting to their beliefs. Flip Flop takes all of the above to an absurd conclusion but the writer is touching on sensitive issues and doing so from an angle that the immigrants aren’t always in the right. The scene where the Slithergee "humbly asks" that Christmas be cancelled because it causes offence to members of the Slithergee Representative Committee is pretty much lifted from the Daily Express’s annual "Winterval" editorial.

Whether the point was to satirise those who see immigrants as selfish and manipulative by taking it to ridiculous extremes (and using giant slugs as the protagonists) or to act as a cautionary tale against the dangers of appeasement, the more politically contentious issues seem, largely, to have been overlooked and the debate has centred around the gimmick. Which is fine because the gimmick works while the political message can be a touch uncomfortable if you take it too seriously.