This is what we found on Wikipedia regarding the Cool Britannia:

Cool Britannia was a name for the period of increased pride in the culture of the United Kingdom in the mid-to-late 1990s, inspired by Swinging London from 1960s pop culture. This loosely coincided with the latter years of John Major's conservative government and the 1997 United Kingdom general election, which Tony Blair's New Labour won in a landslide. Britpop and musical acts such as Oasis, Blur, and the Spice Girls were at the forefront. The term—a pun on the title of the British patriotic song "Rule, Britannia!"—reflects renewed optimism in the United Kingdom after the tumultuous 1970s and 1980s.