With few exceptions, poets who perform in public develop a 'patter' to help the audience grasp the themes, forms and diction of what they read out. They adjust this patter according to the audience they address: schoolchildren, undergraduates and hardened poetry buffs receive different directions, and a different package of poems is delivered to each. An audience is like a variable form into which a poet fits the squares and oblongs of poems, and a poet's patter is the mortar between the bricks. Tony Harrison, an outstanding performer of his own poetry, injected into virtually the same reading to undergraduates, year after year, intense-seeming feeling, and explained in advance each allusion, dialect word, obscurity and nuance, so that the poem came to the ear like an arrow to a bull's-eye, with perfect clarity.

Or was it clarity? On the radio recently a poet drew attention to one of her nicer effects: 'Watch out in the second stanza for...' Like a tour guide, she was making sure that we didn't miss a thing. There was little enough in the poem, and it would have been a shame had we overlooked even that little. The vocations of poet and performer have become intertwined. If a poet performs poorly or - more rarely - refuses to perform at all in public, with few exceptions (Philip Larkin most notably) that poet will find it hard to retain a publisher. In the fast-food world of modern bookselling a book is kept in stock only so long as the writer is visible, moving about being a writer, or being featured in the media. Collections of contemporary poetry by all but the handful of syllabus or entertainment celebrities stay on the shelves for a few months at best. It is hardly surprising, given that more than three hundred new titles each year have a claim to space, that this should be so. After a collection's shop life is effectively over, it enters a performance afterlife, sold by the poet at readings and festivals.

Poets not only create poems: most now also sell them, like the old ballad-sheet vendors. No wonder they learn to talk up the product. But does this pattering affect the product? I've suggested in these columns that public readings affect, for good and ill, how poets write. My concern here is with audience and readership, with the increasing passivity of both before the didactic patter of the performing poet.

Peter Porter suggested a quarter of a century ago that Adrian Mitchell should be compelled to read only to Women's Institute audiences and W.H. Auden to young socialists. The poet should perform against the grain. Reading to the converted creates a reassuring synergy, but the act of reading aloud should be creative for writer and audience. 'Watch out in the second stanza for...' What is the poet doing? Pre-empting - programming the reader's response. In a book we would hardly welcome the intrusion of the poet, admonishing us to laugh here, note a reversed foot there, explaining an allusion, unless it were in a spirit of play, as in the filler notes to The Waste Land, or in an historical spirit, as in the footnotes of David Jones which are so prominent as to become part of the texture of the poetry, not adjuncts to it.

The pre-programming of audiences occurs in various ways and at various stages. A major interview can pave the way for an experimental work; reviewers can be squared or discredited in advance. And at 'grass roots level' there is first person patter. The tools and techniques are those of the spin doctor.

I used to admire the Faber & Faber blurb writers. They provided a sentence or two of description, review quotes, a biographical note, and left it at that. Taken with the often drab covers, this kind of publishing was literary: it was the reader's job and pleasure to discover what was there. The blurb of Touch (1967) said simply, 'Thom Gunn's latest volume of poems includes the text of "Misanthropos" which was broadcast on the Third Programme.' This was followed by a two line quote from the Times Literary Supplement and a longer endorsement from Edwin Muir. But four years later, with Moly, the style had begun to change. 'This new collection of poems by Thom Gunn - his first since Touch (1967) - has been eagerly awaited.' Some poorly-framed review quotes are given, and then, 'Moly is further confirmation of the brilliance and maturity of the poetry that Thom Gunn is writing now.' Not bad, not like the blurbs which claim major and magnificent status for every writer who can sign his or her name; but worse than what came before, a straw in a wind which nowadays carries whole haystacks with it. Make it sound like news ('eagerly awaited'), make it sound authoritative and legitimate ('brilliance and maturity'). Symbols of security. The extended puffing blurb means that surviving independent readers or critics judge the puff as well as, or instead of, the work. So too an audience can judge a performance instead of the poems.

In the age of Coles' and York Notes, of 'right answers' about literature, the job of teachers and critics has changed. They should set out to de-programme students and readers, restore the freedom to interpret, judge and see through the patter to the poem. It's a tall order. Students can feel quite adrift without a secondary text to help them aboard a primary text. They feel safer in the tugboat than aboard the liner even if the tugboat doesn't go much beyond the harbour mouth.

Octavio Paz insisted on the need for an informed and open critical 'space' if a culture were to produce poetry. Writing within an authoritarian context, he had in mind reader and poet. A poet needs informed response, a dialogue with readers. Readers are disempowered by ignorance and repression, just as writers are. But the disciplines of marketing, which many poets now practise on behalf of their wares, can render them deaf to dialogue; teachers who know the right answers because they trust the teller or the approved critic can render readers incapable of dialogue. Expert packaging creates consumers. Good poetry creates readers. Bringing the poem and the reader together in this age of communication is, paradoxically, harder than ever.