Ireland gets a guitar festival next week. A star attraction is John Williams, who has been opening minds to the instrument's charms since the 1950s, writes Anna Carey.

John Feeley (Trinity College chapel, Thursday, July 1st) Feeley is Ireland's leading classical guitarist

Pierre Bensusan (Liberty Hall, Thursday, July 1st) The French- Algerian virtuoso is the winner of the Grand Prix du Disque

Berta Rojas (Bank of Ireland Arts Centre, Friday, July 2nd) One of Paraguay's greatest musicians makes her Irish début

Clive Barnes (Mother Redcap's, Friday, July 2nd) The Wexford man plays lap-slide guitar, drawing on gospel and blues

Rafael (Bank of Ireland Arts Centre, Sunday, July 3rd) The legendary Spanish guitarist pushes flamenco in a new direction'The guitar is a very accessible instrument," says John Williams. "It's cheap, it's quite easy to learn the basics, you can carry it around with you easily . . ."

The Melbourne-born musician has been opening people's minds to the charms of the guitar all his life. When he entered the Royal College of Music, in 1956, the young guitarist had to study the piano and music theory, as the guitar simply wasn't taught in most conservatoires. But the profile of the classical guitar has risen since then - thanks in no small part to Williams himself - and this month sees the launch of Ireland's first celebration of the instrument, the Waltons Guitar Festival of Ireland. The event will showcase the work of guitarists from all over the world, from Paraguay to Wexford.

"Ireland doesn't have its own guitar festival; other countries do," says Barney Whelan, the festival's founder. "And we thought, we've got great guitarists here and a lot of enthusiastic students and fans: why not?" As Williams says wryly: "It's very different now."

Williams has been a celebrated classical guitarist since his first professional performance, in 1958, which prompted the legendary Andrés Segovia to declare: "A prince of the guitar has arrived in the music world." But he has never rested on his laurels. In the 1960s and 1970s Williams branched out, becoming the first classical musician to play at Ronnie Scott's jazz club, in London, a venue where he played until the late 1970s.

Changes, his 1971 album, saw him playing the electric guitar on record for the first time, a move that supposedly outraged purists. Williams says, however, that the classical-guitar buffs weren't quite so appalled at his forays in to jazz, folk and even pop as legend has it.

"The adverse reaction tends to be a bit exaggerated in retrospect," he says. "There was some from what I suppose you could call diehard classical fans, but I don't think it was peculiar to what I was doing with the guitar. You have to see it in the context of the time."

Williams believes the music world was simply more conservative, although that has altered, he says. "There's been a big social change in music over the last 30 years, a greater exchange of knowledge and ideas. Musicians of different countries and musical backgrounds have been working together. People do have an enormous desire to extend their musical knowledge."

And the result is a curiosity about non-Western musical traditions."There's an enormous interest today in what we call world music, by which of course we mean music from cultures other than Europe, and I think that's great," he says. "I think the classical-music establishment is quite keen on understanding that. The London Symphony Orchestra has held some very high-profile concerts with a variety of non-European musicians. This change happens very slowly, but it is happening."

Williams sees the guitar as an instrument that crosses all boundaries, pointing out its ubiquity in music all over the world. "Through the blues of the southern United States and then through jazz, the guitar was the main instrument. The guitar was also prominent in African music. A lot of musicians in Madagascar play what is essentially a Spanish guitar."

And Williams doesn't just pay lip service to other musical traditions. He has performed music from all over the world, and his enchanting most recent album, El Diablo Suelto, sees him playing, not for the first time, the works of Venezuelan composers.

He has long been drawn to Latin American music. "It's easy on the guitar, because the guitar naturally belongs in South American culture: there have been guitars there for 500 years." Williams regards Venezuelan music as fitting right in with the classical Western pieces in his repertoire; they will each make up half of his Dublin concert.

As well as his solo concert, Williams is scheduled to hold what's being billed as a masterclass as part of the festival, although he wouldn't describe it as such himself. "I hate the word masterclass," he says. "I just look at these classes as the opportunity to meet other guitarists and play and discuss different methods. It's not like some sort of examination where I sit in the master's chair and dictate. I like free-ranging, informal classes. I treat it in a very open, conversational way: I don't expect it to be a one-way flow from me."

Williams has always enjoyed teaching. "I visit the colleges of music once or twice a year. I used to teach regularly in the Royal College of Music, but I don't now." Instead he prefers to hold single classes, an approach that suits both his touring lifestyle and his teaching style. "I think the way I like to conduct classes is, by nature, very open: a lot of talking goes on. So taking classes from time to time, wherever I'm visiting, suits that approach. I don't think you need to have a lesson every week to impart what you think is helpful."

Williams is best known for his interpretation of other people's music, and although he does compose he doesn't "just sit down and write a piece. I don't really write a lot", he says. "When I do write music it usually comes from the project that I'm working on at the time. At the moment I've been working with John Etheridge and Patrick Bebey as a trio, and while we're mostly doing Patrick's music I've come up with a piece that suits what we're playing together. But I don't think of myself as a composer. I think of myself as a guitarist who has a good idea every so often, and when I'm working in a group I put that idea to the test and see if it works."

Williams hopes to work more with these inspiring collaborators. "I've always got a lot of plans for the future: I'm always trying things out to see if they work. I just don't know what works yet. But I hope to work more with John and Patrick . We only started working together last October, and we had our first gig together ever a few weeks ago, in Scotland."

This isn't, of course, the first time Williams has collaborated with other musicians. He has worked with everyone from André Previn to, on one remarkable occasion, Pete Townshend. But in 1979 he took what many considered his boldest step, joining with five friends to form an instrumental group called Sky. "I'd worked with other musicians before, of course, but it was a big change to actually work together as a group."

By the time of Williams's amicable split from the group, in 1984, Sky's mixture of souped-up classics and their own compositions became hugely popular, and Williams believes that one of the biggest effects of the group's success was to bridge the gap between classical-guitar and guitar-rock audiences.

"After Sky I think a lot of young fans of popular and folk music actually formed a connection with the classical guitar," he says.

"They felt it stretched out towards them in a way the normal classical establishment didn't. I think that affected the popularity of the classical guitar. And I can see it in some of my audiences today. I think there are a lot of middle-aged people who discovered Sky when they were young, and now they go to classical-guitar concerts."

Dublin's guitar festival has similar aims. Barney Whelan says: "We want to open up guitar music to people who might not have considered going to a classical concert and to classical students who might not have gone to a steel-string guitarist. What I want to see is people trying their hand at different styles."

Williams's stellar career is an illustration of what can happen when people expand their musical horizons. "Most people do think of the guitar as an instrument of rock and folk, but that's OK," he says. "All you can do is try and broaden their minds." The Waltons Guitar Festival of Ireland should do just that.

John Williams is at the National Concert Hall, Dublin, on July 3rd. Waltons Guitar Festival of Ireland runs from June 30th to July 4th. See www.guitarfestivalof ireland.com for more details