In order to do an effective alien voice where your voice is electronically treated it’s best to hear that electronic treatment while you’re doing it, for two reasons. One, once you hear how it’s going to sound its quite exciting and you go with it. You hear the deep voice and you think ‘Oh god, yes, I am a Cyberman!’

And the other thing is, with the clarity and the articulation of your performance, you can’t really gauge it unless you can hear how your voice is driving the voice effect. Not hearing the voice effect you might give what you think is a very clearly enunciated performance, and then in post production they’ll put an effect on it and you can’t understand a word of it.

Likewise with the Daleks. You have to hear the remodulation in order to do it because if you just started shouting into a microphone saying ‘exterminate’ without remodulation it’s just very embarrassing, but once you hear that noise you think ‘Yes, yes, I can do this.’