For such a relatively tiny place, England has had what seems like more than its fair share of great writers; maybe we only think that because we speak the Island language and are more familiar with brilliant Brtions than Milton's peers in Japan or Finland. That's probably partly true, but it's also definite fact that the British Isles have produced some of the finest pens to ever advance the realm of Literature.
London in its various manifestations—as Roman city, Protestant religious center, or war zone—has always been a cosmopolitan common ground for natives and ex-pats looking to stretch and improve their intellects. It's the capital of the United Kingdom, but it's more than that: one of the bastions of Western civilization. The foggy metropolis hosted the first productions of Shakespeare's plays, the starting place for Chaucer's pilgrims, the birthing room of punk rock, the target of the Nazi air blitz, and the location of King Arthur's crowning.
But wait, astute readers will say; Chaucer's pilgrims were literary inventions, and King Arthur didn't exist (at least not as an actual king, certainly not the monarch of a united Britain). And Shakespeare may or may not have existed. And punk rock was invented in New York. Etc., etc., etc.
To which the only possible response is—just because something is "made up" doesn't make it not real (and for all you doubters, Willy Shakespeare was a real dude and punk rock did start in Manchester). The fact that the literary output of the U.K. (not just from London—from Scotland, England and Ireland) has had such an enormous impact on writers and writing all over the world seems to be a case for the actual existence of these inventions. Maybe there was no Summoner who went out looking for Death, and maybe King Arthur was just a Welsh chieftain, or a figment of Geoffrey of Monmouth's imagination, but does that mean they aren't real?
Certainly not. They wouldn't be household words, otherwise; they simply wouldn't exist. But they do, and because of them so does a huge portion of the literary canon. To say that British literature is the "most important" on a global scale would obviously be too great a claim, but there is a degree to which the Isles have always acted as a kind of hub to the spokes of the world's literati. Even a writer as gifted and un-English as Argentina's Jorge Luis Borges noted his indebtedness to William Shakespeare.
Britain's political and philosophical history has leant to this phenomenon, but so has its linguistic history. Fought over by everyone from the Romans to the Danes to the Saxons to the French, each group to come and go (or come and stay, as the case may be) has shaped the evolution of the English language. It isn't a wholly Latinate tongue, or fully Germanic, or entirely Scandinavian—it's all of the above, and consequently far more versatile than any more historically coherent language.
Writers in English have consistently reflected this linguistic adaptability in their commitment to advancing literary technique and scope. In other words, British writers love their language. They twist it, they beat it, they temper it, they mold and rennovate and feed it, all because they're intoxicated with its cadences, its meanings, its complete surrender to a good writer's whims.
The English-speaking world today is much broader than it once was, but the debt its writers owe is still to its place of origin. The Isles are the capital of English letters. It's where Beowulf and Sir Gawain and the Green Knight were written, the place where James Joyce, William Shakespeare, John Milton, Charles Dickens and Graham Greene were all born, the origin of the Romantic movement, the adopted homeland of Joseph Conrad and T.S. Eliot—basically one of the world's truly great and prosperous litrary havens throughout recorded history.
Our point isn't to turn everyone into Anglophiles. For all its bright spots, Britain's literary history has some pretty lowly lows. But if you love good writing (as we trust you do, or why would you be here?), British Literature includes some of the créme de la créme as the French say. A word to the reckless: proceed with caution, lest the wonders ye behold draw ye into their clutches and never relase thee.