The 1985 edition of Geoffrey Hill's Collected Poems was, by comparison with this, a very slender thing. We had reason, then, to assume that there would not be much more: he had been ill, and depressed; and what is the productive life span of a poet anyway, especially one whose subject, so often, is "the tongue's atrocities", the culpability of words and the responsibility to use them with immense and utmost care, if at all? The next 13 years of silence, apart from lectures, would have encouraged such pessimism. And then, from Canaan (1996) onwards, the dam burst; there were nine collections after that. By the time the 1985 collection ends in this volume, we have a further 800-odd pages to go. If there is a paperback or second edition of his Collected Poems next year, will it be a third as long again as this one? (Remember Hill's epigraph to "Hymns to Our Lady of Chartres" – "As Henry Adams observed at Chartres, the twin powers of the modern world are inertia and velocity" – and note that inertia makes things hard to stop, as well as hard to start.)

From the word go, Hill gave some of his readers problems with his style, which, to use the most boring word about it, is "difficult", and there was some small, perplexed part of me that hoped one of the reasons this book is so big is that the answers are printed in the back. The editor of the 1960 Penguin Book of Contemporary Verse, Kenneth Allott, in argument with Hill about which of his poems to include (Hill apparently objected to the inclusion of "In Memoriam Jane Frazer" on the grounds of its "coy last stanza", and of "The White Ship" because of its "shaky technique"), said of the poem finally chosen: "I understand 'Annunciations' only in the sense that cats and dogs may be said to understand human conversation, ie they grasp something by the tone of the speaking voice, but without help I cannot construe it." Hill did give help in that collection, of a kind he has been reluctant to provide in public ever since, and although his gloss is not what we might call conventionally explanatory, it provided his readers, almost from the start, with something approaching a key to how to read him.

"The Word (line 1) is the impulse that makes and comprehends. Poetry before the poetry-banquet ... What I say in the section is, I think, that I don't believe in the Word. The fact that I make the poem means that I still believe in words." "Annunciations" ends with the lines:

... Priests, martyrs,

Parade to this imperious theme: 'O Love,

You know what pains succeed; be vigilant; strive

To recognize the damned among your friends.

Hill says: "But I want the poem to have this dubious end; because I feel dubious; and the whole business is dubious." He's not wrong: and that sentence, balanced on the fulcrums of its semicolons, alerts us to the delicately measured nuances of these lines. Is "parade" an imperative or the present tense? (Or even a noun?) Is "Love" a person or an idea? ("Love" is, in Hill, very often the former.) Does "succeed" mean "win" or "follow on from"? And, perhaps most crucially, are we meant to keep our distance from the damned or attend to them? These deliberations we are obliged to make are, to use his words from another poem in the same collection, "poised, unanswerable"; not an abnegation of duty but an unparaphrasable recognition that these are matters we are not qualified to make a final decision on.

Which can bring us to Hill's politics. In 1985, Tom Paulin wrote for the LRB a review of a collection of essays about Hill published by the Open University in which he attacked Hill for "kitsch feudalism", and all the contributors bar one for "reverential gullibility". The very title King Log – a reference to Aesop's fable about the frogs who wanted a king – is, he asserted, "reactionary in its implications", and he berated one of the contributors for not watching Channel 4 and so realising that we live in a pluralist society. (That's an injunction that has lost its force, you feel.) The correspondence that this piece inaugurated rumbled on for 10 months. Broadly, the case against Hill tends to have been that he is too conservative, too burdened by the past, for his or our own good. Much has been made, though to no conclusive end, of the allusions to Virgil's blood-foaming Tiber made both in one of Hill's Mercian Hymns (begun in 1968) and Enoch Powell's notorious "rivers of blood" speech (also 1968).

But this is a slur by association, as even a skim-reading of Hill's verse will attest. Horror at all kinds of political violence is found throughout his work: from his most anthologised poem, "September Song", with its haunting epigraph "born 19.6.32 – deported 24.9.42" (Hill was born one day earlier), to "On Looking Through 50 Jahre im Bild: Bundesrepublik Deutschland", which ends with a description of Willy Brandt kneeling at the Warsaw ghetto memorial in 1970, and the line: "I did what people do when words fail them." That is: kneel in supplication, or in silent prayer.

Words have not failed Hill; but the long silences between his collections up to 1996 suggest that he knows what it's like when they do. Now, it seems, he can make them do what he wants, and if the phrase "greatest living poet in the English language" has any meaning, we should use it now. He has many voices, not excluding wit and playfulness. The very title of his 2000 collection Speech! Speech! – both conventional after-dinner request and surprised exclamation – is a joke. The poems inside were almost anti-lyrical, recalling the rushed-memo style, capitalised phrases and obscure references of Pound's more gnomic Cantos. "I follow MacDiarmid in desiring 'a learned poetry wholly free /Of the brutal love of ignorance'," Hill wrote in his 1986 essay collection The Enemy's Country, and some feared that he was becoming too allusive, and that the time when he could write a lyric of poignancy and grace like that from 1978's "Ave Regina Coelorum" – "There is a land called Lost / at peace inside our heads" was gone for ever. His abandonment of rhyme, for which he had an almost incomparable skill, made me fear he no longer had total mastery over what he was saying.

It was a groundless fear. The sequence Clavics (2011), with poems laid out on the page in shapes suggestive of a key, and a pair of outstretched wings, shows someone literally shaping words to his will; and the final sequence of Broken Hierarchies, "Al Tempo de' Tremuoti", is as tight and as austerely beautiful as anything he has ever done. Yet sometimes it is not austere at all:

I can see someone walking there, a girl,

And she is you, old love. Edging the meadow

The may-tree is all light and all shadow.

Coming and going are the things eternal.

You can hear in those lines many things, picked out in the simplest words. I hear in them a comprehension of destiny, of life and death, an acceptance both heartbreaking and peaceful at the same time. It would appear the answers were in the back after all.