I was lucky enough myself to have been in Dad's Army for an episode.

But here I am today recording this and I'm in the studio with all the others on a clean mic. It's extraordinary, the actor's found a way of doing it for himself.

Got through it without fluffing, that's the main thing any actor can hope for.

It couldn't sound like a dog, because K9 isn't a dog, but I made it sound as mechanical as possible.

It was just at the end of the golden era of BBC comedy, which was fantastic.

Martin Jarvis was to have played the part originally but I think I had longer hair or something, I know not.

No, I'm at full height, I'm in the studio, I can actually catch actors by the eye, it's fantastic.

Dick Mills was in charge of sound effects and all the rest then, and he put the voice through a ring modulator or whatever gizmos he'd got at the time to make it sound a little more electronic.