Peter Kavanagh is proud of his brother's poetry. In fact, he says, he is largely responsible for Patrick Kavanagh's reputation, reports Patsy McGarry.

He is 88 and says he is ready for the grave, but the evidence is not convincing. Dr Peter Kavanagh is in robust form at Trinity College in Dublin, where he is taking part in a public interview with the Irish Times journalist John Waters, one of the events to mark the centenary of the birth of his brother, Patrick.

Kavanagh's feistiness is a hit with the 300 or more mainly middle-aged Patrick Kavanagh fans in the hall, who rise to their feet to give him a standing ovation at the end. Some are no doubt impressed by his acknowledgment of his volatility; many sympathise with him about a legal problem that means his books, which include a biography of his brother, are unavailable in Ireland.

These are books that he describes with characteristic assurance as the canon of Patrick Kavanagh's work. He is similarly candid when he is asked who his brother's greatest influence was. "Myself," he replies succinctly before inviting the next question. And later he describes himself as the sacred keeper of his brother's sacred conscience.

The ovation also owes some of its length to glee at his colourful pronouncements on Irish literature. They begin with poetry - for which there can be no definition, he says. "There is good verse and there is bad verse, but there is no such thing as good poetry or bad poetry. It is a unique element. The professors don't know what they are talking about, which is normal for our professors."

"Poetry is closely allied to theology. More so with prayer. The experience, as I see it, is really prayer. Patrick believed in the divinity, so what he hoped was to get a flash of that beatific vision, that supernatural place. Words are the least important part of it. In a poem words burn up in a tremendous thread of something unusual. So if I say there are no poets in Ireland today it is based on that. All these versifiers are poets according to themselves."

Twelve years younger than Patrick, he "realised from the age of 10 we were dealing with something unusual". When Patrick died, in 1967, Kavanagh gave up his English professorship, in Wisconsin, to devote his life to a "moral obligation". After the funeral, in Dublin, he went to Patrick's flat, where he and his sister, Celia, tied the manuscripts up with a rope. "It was a rat's nest of papers, cuttings, etc. For the best part of a year, with a steam iron, I smoothed out the pages - for nine to 10 months."

Before that there were "no works", he says, "just a stack of papers with no continuity or form. That was how Patrick operated, and that is what he left me: a heap". He pieced them together, collated and edited them. "From these the Complete Poems emerged. Fifty per cent of the titles of Patrick's poems are by me."

Between 1967 and 1980 he published Lapped Furrows, November Haggard, Garden Of The Golden Apples, Complete Poems, Sacred Keeper, Love's Tortured Headland, Savage Rock, The Dancing Flame and By Night Unstarred.

Sixty years ago, in 1944, he graduated from Trinity with a doctorate in Irish theatre and went to the US to teach. He says he corresponded with Patrick almost every week. "He didn't want to talk about trochees or spondees, all that rubbish - did this poem have 'the flash'?" he says.

"There are two realities for the poet. There's the reality here and the spiritual reality of the world that surrounds us. The poet, in his most intense form, stands on the line between the two worlds and occasionally crosses over to the spiritual world and brings back something unique."

He recalls Patrick's life in Dublin as improvident. "He was treated very badly. No one gave him anything. I supported him, but I was in poverty myself, on $11 a month as a teacher." He believes a lot of Patrick's work was stolen in Dublin. "He was so careless, trunks full of old scraps."

As for Patrick's best work, he wonders who decides to call a man a poet. "The newspaper critic? The university professor? Most haven't a clue. I believe it's the people. Poetry is decided by you, by the mob. Ultimately, time takes over. That is why, since he died, his reputation has continued to increase, why so many [of his poems] have been taught."

His best poems came "after the devastating law case" - [a libel action that Patrick Kavanagh lost] - when he was opposed by the most pernicious element in Dublin society." Patrick had lung cancer. He was surviving on alcohol, betting on horses. But "what he lost in power he made up for in technique". He "never acknowledged anything. He picked up everything useful to him. 'You should be delighted,' was his attitude. He drove me up the wall", but "we never had real rows. We were like Siamese twins".

He recalls an evening 60 years ago, at the Shelbourne Hotel, when Patrick showed him a draft of Raglan Road. He was bringing it to the Irish Press. It had no title and had a line Peter didn't like. It referred to "synthetic sighs and fish-dim eyes and all death's loud display". Patrick went off to reconsider, and the line became: "The Queen of Hearts still making tarts and I not making hay."

The Great Hunger was "tour-de-force verse writing". It was "more me than Patrick, in some ways. I urged him to write it. The harsh world was killing his spirit". He finished it in 17 or 18 days. But a poet "has no damn business dealing with social issues".

The novel Tarry Flynn was the same. "He thought it was very good. I told him I didn't think a hell of a lot of it. The only reality is the reality within oneself. One's journey. Only the self is a matter of any importance. All you have is individuality, part of your soul. It is the only unique thing in the world."

The poet "is a moralist who speaks to humanity. He doesn't speak on individual issues. He is like a psalmist". He is "not a social writer. He leaves that to the versifiers and politicians".

Talking about Patrick's spirituality, he describes him as "a conservative Catholic to the last - period, full stop, exclamation mark - [but] he may not have been a Catholic of the Lourdes or Fatima variety, as he said himself".

Peter Kavanagh questions whether there is any such a thing as an "Irish" poet. He describes Yeats as "a poet in action . . . a good writer of verse, delightful stuff tingling like a xylophone. But there's nothing to it." He compliments Swift, in a manner, and says Goldsmith wasn't bad, but "after that things get very scarce, up to Mangan. But he's always complaining . . . Dark Rosaleen and all that stuff. Joyce came close, but I don't rate him either. Then it's a very barren field".

Nor did Beckett have what it took. "I heard Krapp's Last Tape. It didn't do much for me. I tried to read him. I liked the man. We corresponded, and he contributed to a cash fund raised for me. His work was experimental. It doesn't do anything for me."

Then he talks about contemporary Irish poets. Seamus Heaney is "a rather delicate tea-time verse poet popular in New England and [with] the Princeton group, that whole group of literary morticians." And he believes Brendan Behan belonged in a circus. Only Robert Burns, " a poet of genius", has his admiration. And some Irish ballads, such as Molly Malone, are terrific.

As for Patrick the man, he says, he was "kindly, very kind, stiff and very conservative. He would not allow anyone call him Paddy". He was "extraordinarily healthy". He "worked the fields and was a cross-country runner". He was very interested in athletics and played "that barbarous game called Gaelic football".

Seamus Heaney will talk about Patrick Kavanagh at the Patrick Kavanagh Centre, Inniskeen, Co Monaghan, on November 26th; on October 21st, the day of the centenary, the National Concert Hall will host a commemorative evening