My best guess would be sometime around or just after the early 1960s, when the fashion for "trad" jazz music (along with "flapper" dresses and raccoon coats) was revived? By the way, if you ever get a chance to see the 1962 film "Ring-A-Ding Rythm!" (original title It's Trad, Dad!), it's wacky fun! It was the first feature film directed by A Hard Day’s Night director Richard Lester. From TCM: http://www.tcm.com/this-month/article/150482|0/It-s-Trad-Dad-.html "...London was in the midst of a British jazz revival driven by the music of New Orleans and Dixieland and this is the sound that inspired It's Trad, Dad (1962, aka Ring-a-Ding Rhythm), which also marks the feature film debut of Richard Lester, whose subsequent film was A Hard Day's Night (1964) for The Beatles. Subotsky didn't just stack the deck with jazz groups though; he also added a generous helping of current pop acts and even tried to scoop Katzman with showcasing Chubby Checker in the new novelty dance, the twist (Katzman still beat him to the punch with Twist Around the Clock which was released first in the U.S.). The threadbare plot - two teenagers organize a music festival in their small town despite resistance from the mayor and his closed-minded supporters - is merely an excuse to string together an array of musical acts - 26 in all! But what distinguishes It's Trad, Dad from countless other pop music film pastiches is the stylish look and sense of fun that Richard Lester brings to it plus the impressive array of musical talent which covers the pop spectrum from Dixieland (Kenny Ball and His Jazzmen) to rhythm 'n blues (Gary "U.S." Bonds) to ballads (John Leyton) to rock 'n roll (Gene Vincent)."
