While it's true all of Western Europe is guilty, there's a reason why people point to Britain first and foremost. Its empire was pretty much the codifier of what people think of when the word "superpower" is used. There wasn't such an uncontested concentration of power in a single polity that could be projected globally until the UK came out on top from the Napoleonic Wars then went on to subjugate Asia and Africa by the mid-late 19th Century, essentially becoming master of the world market and trade networks (at least until the onset of WWI). Not even the Spanish and Portuguese Empires held such a monopoly. Even after the start of Britain's terminal decline into becoming America's lapdog in the cold war, it still influenced world politics in ways that still affect us today (relevantly, it was originally Israel's patron power before the US supplanted them sometime in the 70s/80s).