James Morris famously changed to Jan Morris in the 1970s. In recent years she vowed not to write another book - but she has one up her sleeve, writes Rosita Boland

The voice is unexpected, to the point of being disconcerting. The Welsh writer Jan Morris is standing on the stage of the Town Hall Theatre in Galway, a participant in this year's Cúirt International Festival of Literature. She's reading from her account of breaking the story of the first successful ascent of Everest. And she sounds exactly like a man. If you weren't looking right at her, all smiles and fluffy white hair and chunky necklace, rather like a personable grandmother, you would think you were listening to a man. The thing is, of course, Morris used to be a man.

In 1972, in Casablanca, James Morris famously underwent a sex change and has been known ever since as Jan Morris. She wrote about the experience in Conundrum (1974), and about the decision which led her there: the lifelong conviction that she had been born in to the wrong sex. Even today, three decades later, high-profile sex changes are virtually unheard of. Convictions notwithstanding, it must have taken a remarkably strong character to go through such a private process in a very public arena.

There are a lot of fans in the Galway audience, and the reading, peppered with polished anecdotes, gets a warm reception, particularly when Morris produces her trademark version of a handkerchief: a hotel facecloth.

"This one is from the Mandarin \ Hotel in Hong Kong," she proclaims, before wiping her brow with it and telling the audience that she always carries a similar version in her handbag, because it is such a useful object. "You can even clean a windscreen with it," she announces brightly to howls of laughter.

People have come loaded with books to be signed, and it takes Morris a full hour after the reading to sign them - a public compliment to, and endorsement of, her work.

Back at Brennans Yard Hotel Morris sinks in to one of the squashy couches in the residents' lounge and waits for a cup of tea to arrive before she revives.

The previous day she drove over from her home in Wales - she is 78 and evidently still tough. Close up she looks younger and also less grandmotherly than from a distance. Her jawline is still that of James Morris, as are the set of her shoulders and the size of her hands. And she has a direct and quite steely way of staring, which she does throughout the interview, entirely unabashed. Perhaps it comes from three decades of being stared at herself.

James Morris was born in 1926 in Somerset, in south-western England. He attended the choir school of Christ Church, Oxford, from nine until 14, then boarded at Lancing College, in Sussex. After leaving school he worked for a short time as a reporter for the Western Daily Press, in Bristol, before joining the army at 17. As an intelligence officer Morris served in Palestine, Egypt and Italy.

Back in England, in 1949, he married Elizabeth Tuckniss, the daughter of a Ceylon tea planter. He went on to Oxford to read English for two years, and in 1951 joined the foreign desk at the London Times as a subeditor. In 1953 he was dispatched to cover John Hunt's Everest expedition.

Morris was the first reporter to break the news of the successful attempt, a story that was carried on the same day as Queen Elizabeth's coronation. It was a true scoop in the old-fashioned sense of the word, one that is impossible to think of breaking in print today, in a world of 24-hour news coverage. It says a lot about how journalism has changed in 50 years to know that Morris's scoop was printed on an inside page, not on the front page, and that the story had no byline, as was normal in those days.

Like many of Morris's experiences, covering the Everest expedition became a book: Coronation Everest (1958). His first book, Coast To Coast (1956), detailed the journeying he did across the US with his family after Everest. His second, Sultan In Oman (1957), recorded his journey across south-eastern Arabia as a guest of the sultan of Oman in the days when nobody had heard of junkets and political correctness.

There followed close on 40 other books and countless magazine and newspaper travel articles. Some of the books now seem very dated; others are out of print.

The best-known volumes these days are Venice (1960), Oxford (1965) and the Pax Britannica trilogy, about the British empire. Trieste And The Meaning Of Nowhere (2001), a lyrical, layered meditation on a city and on ageing, brought Morris new readers and some of her best reviews. She considers it her finest book.

It's the obvious question: does she ever feel that her sensibility as a writer changed when her sex did? "I don't know, to tell you the truth," she says, sipping tea.

But then she says of the Trieste book: "I couldn't have written that book as a man. And it expressed more of me than any of my other books, expressed more of this dual nature of mine than any other book I've ever written. So my writing style stayed the same - but sensibility, of course, that's different."

Morris dislikes being described as a travel writer. "I write about places, but I don't travel," she points out. She has read Dervla Murphy but never met her. "She's an awful lot braver than me!" she says, in a rather tongue-in-cheek way. It's certainly intriguing to imagine Murphy and Morris sharing a stage in a public debate about their work: what on earth would they make of each other?

Morris lives in Wales, near Portmeirion, with Tuckniss, whom she now describes as her partner. They had five children together, one of whom died when a baby.

When Trieste And The Meaning Of Nowhere was published, Morris declared it would be her last book. During the reading earlier, Morris talked about writing a book for her children and grandchildren, a book of advice about life that she wouldn't publish. She talks a bit more about it now. "When you get to my age and you've got children, you often wish you had been more lucid when you were younger, to tell them a bit more about life," she says. "This is what I'm writing for my children and grandchildren."

How many grandchildren does she have? There is a pause. Then Morris says: "Five, I think." There is a longer pause. "I forget, because they're by several different mothers," she offers after a while and laughs. It's an odd moment. Usually, when you ask grandparents about their grandchildren, not only do they know how many they have, they quite often also rattle off their birthdays. But Morris isn't sure how many grandchildren she has, despite the fact that she's writing a book for them to read in time to come, a book about her meditations on things she's learned in life. It seems, somehow, contradictory.

Then I ask how old their daughter was when she died. Again, a pause. "A matter of months," she says. Then, "I'm not exactly sure. It was one of these cot deaths." Again, this lack of knowledge of simple factual information about one's flesh and blood seems unusual. I realise suddenly that Morris is talking like a rather boorish man. Women, in general, are better at remembering things such as grandchildren's birthdays and what age their babies were when they died. Then I wonder if I'm being sexist and feel confused. All in all it's quite a bizarre exchange.

At the end I ask if there is anything else she would like to say. "You haven't asked me about animals," she says straight away. "Animals are very big in my life." How many animals does she have? "One. A Norwegian forest cat. Called Ibsen. He's a big hulking old thing. He always gets mentioned in my interviews." She's not joking, either. She really does want me to put her cat in to the article.

Jan Morris may be a famous Welsh nationalist, but she's all English in her love of the pet.