Our sound designer Gareth Jenkins, the man responsible for creating all the soundscapes and voice effects, makes a brief cameo appearance in this episode.

During the scene in which Skagra is struggling to regain control of the Doctor's TARDIS, the script suggested that only the possessed Chris should intone the words 'Under control'. During the post-production process I decided that this sounded wrong, and that we needed to hear the Krargs chanting the phrase alongside Chris, so Gareth stepped into the breach and contributed not one but a whole gang of Krargs.

Talking of Krargs, Barnaby Edwards provided a tour de force when recording his death scene at the Krarg Commander. There's quite a crowd in that scene, and while I was in the main studio with the other actors, Barney was roaring away in an isolation booth. I asked him to give us more than we'd eventually use, because in action scenes it's always useful to have a little extra so-called 'wildtrack' material at our disposal during post-production. So he roared his way to several sticky ends, earning himself a round of applause from Paul and the rest of the cast!

I can't finish without mentioning something I haven't yet touched upon, which is Russell Stone's brilliant score. Incidental music makes an important contribution to the mood and atmosphere of any piece of drama, and Russell's music for Shada surpassed my expectations. Always sympathetic and never obtrusive, it plays a fundamental role in the final sound picture.

I mention it here because, like the script itself, it reaches something of an emotive peak in those lovely final scenes in part six. One of the many things at which Douglas Adams excelled was writing unsentimental but beautifully evocative farewell scenes, as you'll know if you've seen the TV version of Hitchhiker or the Doctor Who story City of Death. With a little help from Russell, I think our cast brings the final curtain down on Shada in an equally tender and suitably wistful fashion...