A short, heavy-set British character actress, Margolyes has performed primarily on the stage and radio, generally in eccentric comedy roles often requiring her to play older than her years. After studies at Cambridge, she began acting in radio with the BBC. Over the next decade Margolyes' ripe delivery could be heard everywhere in radio spots and TV commercial voiceovers, including a stint as a seductive rabbit plugging Cadbury's Carmel Bunny candy and as a charwoman chimp for a tea ad.

Margolyes did not act regularly in film until the mid-1970s, and for a time most of her roles were in