This is from an educational film called Alice in Label Land, put out in 1974 by the Ministry of Agriculture, Fisheries and Food to promote the new Labelling of Food regulations.
Yeah. Anyway, check out the bloke reading the contents of the chocolate pudding - I swear it's the clever old knight from the Dark Towers songs!
OK, he doesn't look quite right in that picture, but on the TV version it's seriously the same design - the face, the hair, the breastplate, the tasset thing, the round bits on his knees & elbows... EXACTLY the same.
So he wasn't created just as a song character to fit in with the Dark Towers gimmick - he was like a famous educational film star or something, hired on for the Look & Read job! I wonder if the Magic E Wizard or Bill The Brickie ever did any government work?!