While this article in the Times by David Millibank has a generous dollop of political bravado (I could almost hear Land of Hope & Glory swelling as I read it!), it does describe a very interesting perspective: of countries trying to find their place in the globalised world.
Russians getting annoyed with Estonians, Iranians taking to the streets after dodgy elections, Somalian pirates taking on whatever seems to float past, be it yacht or frigate... As we evolve from full-on war to information (media) activism, it seems that both unconsciously and deliberately, most countries are trying to find their global niche. It's no longer enough to have a jostle with the neighbors. As a nation you have to join a pack or risk being picked off or marginalised by one of the other packs.
To me, 'Great' Britain is still a historical term, but that's not to demean it: Britain was the first to industrialise and to globalise. Followers may have perfected it, but there's still an advantage to having done it first, that Milliband does touch on: the relationships and connections that span the globe. In corporate terms, Britain created the market, and while there are now bigger players in that market, they all know who to turn to for guidance about the market.