The legacy of Mary Whitehouse

From the end credits of the 2008 telemovie Filth: The Mary Whitehouse Story, which features Julie Walters in the title role, the final title card details one of Whitehouse's 'victories' over the permissive BBC in 1972:

I was planning to embed the actual clip - from the post-Xmas episode of Top of the Pops on 28 December 1972 - but only until I watched it and realised the bell-related illustrations were provided by a sketching Rolf Harris. So maybe not. To be honest, it is a dreadful song too. And it's definitely about a penis.