As hilarious as it is, it never was aired. Found the following information after I felt this had a little too much of an "Uncle Don" feel to it.
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As much as we would love to believe that this episode of rainbow was actually broadcast to us in our innocent youth, the truth has in fact come out. Rainbow fan-site, Rainbow.web.com offers the following information on it's FAQs page:
"Although often introduced as the unaired pilot, this episode was actually specially made by the team at Thames Television. Geoffrey Hayes told us, "The VT department of each ITV company, every Christmas had a competition to enter all the outtakes from their particular companies programme output, and see which ones were the funniest. But ours wasn't an outtake, we specially did it. It was specially scripted and we did it and I never saw it! We did it and Thames won it, but what they actually won, I don't know. But I never saw the video. I can't remember much about it except for Zippy with a banana." The script was written by the voice of Zippy and George; Roy Skelton."
