Whether anyone is planning a celebration, I don’t know. But 2012 is an important anniversary, for it is – as far as any single year can be – the centenary of the invention of modern poetry in Britain. A big claim; but the linguistic, rhetorical and formal territory occupied by most contemporary poetry is still, really, the one mapped out by two movements which defined themselves publicly in 1912. If you look at most poems published in Britain this year, or indeed in any year back to the 1920s (when the proclamations of 1912 had had time to take effect), you will find them occupying territory somewhere between the principles of the Georgians and those of the Imagists.

Often seen as irreconcilable opposites, the two tendencies are best viewed as poles between which poetry has tended to oscillate ever since. They are the limiting cases of which poets and critics are vaguely aware when thinking about poetic form and language. Not so much (to use Frost’s well-worn metaphor) a tennis net or the lack of it, as lines marking the boundaries of the court. Go too far outside them one way or another and you are likely to lose your audience, alienate your critics, and bore everyone senseless.

Stories of what happened in 1912 have often been told, tendentiously, from one viewpoint or another; but it is worth outlining the whole thing, not least because it is so remarkable that all of it should have taken place ...