School Monitor Pin [Series III]

Often mistaken for a prefect badge, this blue & gold pin can be found to the left of Lister's Federal Marshal pin on his screen-left lapel, throughout Series III.

This is the closest example I've found in terms of matching both colour & typeface, though I feel a softer enamel version would be even more screen-accurate. Yes, it's going to be that type of blog.

Measures approximately 30mm across.