Initially, Gale was one of several rotating partners who worked with Steed (the others being medical man Dr Martin King and nightclub singer Venus Smith).
In keeping with The Avengers' policy of avoiding direct references to romance between the two leads, however, it's quickly stated that Steed is actually sleeping at a nearby hotel.
Her later mode of dress — a leather outfit designed to make it easier for Gale to fight — started a fashion trend, as did her wearing of what were dubbed "kinky boots".
She was replaced by actress Diana Rigg as Emma Peel, who continued Gale's habit of wearing leather during action sequences until she was given her own unique costuming when series production switched to colour.
"[1] In the British Film Institute's 1996 tribute book, The Avengers, Toby Miller writes: "Mrs Gale was known from the first for her clothes, designed by Michael Whittaker with a view to being six months ahead of women's fashions.
She wore knee-high boots, tailored leather suits and a trench coat at a time when such outfits were only seen in porn magazines and fetishist outlets.