Hitler Moustache came from a slightly childish conceit: why is the toothbrush moustache only associated with Adolf? Why not Chaplin? Surely it wasn't the moustache that was responsible for the Nazi's atrocities? Was it possible to claim it back for comedy?
I wondered what would happen if I sported the moustache in public. I correctly guessed that I would become the victim of this "joke" (I had to keep the ugly thing on my face for a year), but it was interesting how bad it made me feel. Hardly anyone said anything directly to me about it, but I felt uncomfortable and in danger. I got an understanding of what it feels like to be silently judged by your appearance.
I had always been troubled by the liberal paradox of wanting everyone to be treated the same, while at the same time respecting their cultural differences. I wanted to examine my own hypocrisy as much as the obvious wrong-headedness of racists. At a close friend's house at Christmas, I realised that, although I had known him for 20 years (and he'd told me many times), I could never remember what his ethnicity was. It was embarrassing, but it would also be embarrassing to ask.
Clearly I should know and I should respect his heritage. Didn't the fact that I always forgot make me the same as a racist who would just call him "Chinese"? I knew there was something comedic in this internal conflict, but also wanted to articulate that moment when a desire not to appear racist crashes against my other liberal instinct that we are all ultimately members of the human race.
It seemed a comedically appealing idea: that in one sense a racist seeing the world as just four types of people is closer to the ultimate goal of us all being equal than a liberal who sees us as 195 distinct flavours. It took me months to formulate a way of expressing this and even then I was worried about performing the routine and kept putting it off. Precision was vital.
And I had to decide if I was going to use racist language in the piece. I was reluctant, which just made me consider the power of words even more. But to show the offensiveness on both sides of the argument, I felt I needed them. Are the words any more upsetting than our habit of manufacturing cultural differences in order to justify conflict? And can a word be offensive in itself? As I say elsewhere in the show: "a stone is not a weapon until you throw it at someone."
I wanted to unsettle and confuse people because this is not as simple a subject as we seem to want to make it. I love the ambiguity in the routine: it's not telling you what to think, just asking you to question your own assumptions as well as those of others. It's easy to pass judgement on someone else's racism, but what about your own? Every subject has nuance, though (ironically) even many liberals want to see everything as black and white ...
• Richard Herring performs We're All Going to Die! on 22 and 23 May at the Bloomsbury theatre, London.
From the archive: the Hitler Moustache debate
Brian Logan: stand-up comedy's new offenders
Richard Herring: there isn't a 'New Offensiveness'
Brian Logan: reporting on comedy's new offenders wasn't intended to offend
Reader's editor ... on squeezing the whole show into a few lines