When I first heard the epithet Britsmy stomach turned because it just oozes self-love. You do not give YOURSELF an affectionate nick-name; you leave that as the prerogative of other people, and if you want to use affectionate nick-names, then it is appropriate to bestow them on others. The BRITS are suffering from a very severe doze of NARCISSISM!
Alan Titchmarsh is a major offender. He loves the term. He is currently doing a TV series called THE NATURE OF BRITAIN. This is going down very well in Britain, but it is merely a very unhealthy exercise in self-love!
I can tell you the nature of Britain in a word: daffodil… oops … that is to say, Narcissist.