SWINGIN’ LONDON :

expression used by U.S. journalists to explain why London had become the capital of fashion and culture.
In England, "Swingin 'London" is the time of the mini-skirt, the release of decency..

It's also time series: "bowler hat and leather boots" and "The Prisoner".

This is also a musical footprint, yet indelible to this day, with bands like the Beatles and the Rolling Stones