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 throughout the mid and second half of the 1990s, inspired by Swinging London from 1960s pop culture. This loosely coincided with John Major's conservative government and the 1997 United Kingdom general election where Tony Blair's New Labour government won in a landslide. The success of Britpop and musical acts such as Oasis, Blur and the Spice Girls were at the forefront which reflected a renewed feeling of optimism in the United Kingdom following the tumultuous years of the 1970s and 1980s. The name is a pun on the title of the British patriotic song "Rule, Britannia!"