'A Derry jazz festival? Are you off your head?'

When Johnny Murray first put forward the idea of an annual jazz festival in Northern Ireland's second city, staff in one Londonderry bar told him he was "off his head".

"Jazz will never work in Derry," he was warned way back in 2001.

Twenty-five years on, the City of Derry Jazz Festival is marking a major milestone drawing major international artists, filling hotels and thrilling ever growing audiences each year.

But its success wasn't just surprising to the city's bar staff, even Murray didn't expect the festival to expand the way it did.

Over the bank holiday weekend more than 400 performances are set to take place across 70 venues in the city, with about 100,000 visitors expected to take in the festival.

The idea of a jazz festival had been in the works for a long time with its origins being traced back to the opposite end of the island during a trip to Cork.

Murray, well known in the north west as manager of the city's Rialto Theatre, was visiting with fellow festival founder Gerard McColgan for the city's jazz festival when they thought maybe this was what their hometown was missing.

Derry was, he said, a city with "a gap in its events calendar" that maybe a "jazz festival could fill".

But like any bright ideas, it wasn't without it's challenges – namely do the people of Derry even like jazz music?

Murray told BBC Radio Foyle's Mark Patterson Show one decision taken in those formative years would prove crucial in shaping the festival's future – Derry's take could not be confined to the purists - this, he said, would be a festival for all.

"If it had been pure jazz, you'd have had a very limited audience," he said. "We wanted it to be commercial and accessible — so that everybody could participate."

From the outset, the festival embraced musical diversity: big band, swing, ska, blues, Dixieland and bebop.

"People would say 'I don't like jazz' - but the festival is much broader than that."

Convincing the city's many bars and clubs to take a punt on a new festival was the next hurdle.

"When I went to the bars, the reaction wasn't encouraging," Murray said .

"They just didn't think it would work. I remember one bar saying to me 'are you off your head? Jazz will never work in Derry'."

Murray proposed a modest experiment. He asked each bar he approached to book one act in that first year.

They were urged to "see how it goes" and to "have faith". The following year venues were asked to take two bands.

With each passing year, momentum gathered. More and more venues were booking more and more bands.

"And it just built from there," Murray said.

Around 6,000 people attended events in the festival's first year, a figure dwarfed now by the numbers of people set to enjoy the May bank holiday weekend music.

Over the years, it has attracted internationally recognised artists.

Jools Holland, Ruby Turner, Van Morrison, Billy Ocean and Bill Wyman have all played the festival. Acclaimed jazz performers Soweto Kinch and Bobo Stenson have wowed audiences.

Equally important to the festival's success, Murray said, are the local musicians, those who "were there from the beginning" - Gay MacIntyre, Johnny Quigley, Jackie Flavelle and Jimmy Gilchrist.

The festival is now worth around £2m to the local economy.

Its continued growth, Aisling McCallion from Derry City and Strabane District Council said, reflects "the enduring popularity and ambition" of the festival.

Opportunities for younger musicians have expanded steadily too - schools and youth ensembles are now an integral part of the programme.

That, McCallion said, remains a key focus, and gives "young and up-and-coming musicians the chance to develop their skills and perform in a professional setting, establishing a lasting legacy for the festival".

Organisers say the festival's silver anniversary edition reflects both its international reputation and its long-standing connection to the city's live music scene.

Curtis Stigers performed in the city earlier this week, so too Donegal blues guitarist Muireann Bradley.

Leo Richardson, Guy Davis and Sylvie Noble are also among those playing the festival this year.

Scores of venues across the city play their part hosting the festival, including the Millenium Forum, New Gates Arts Centre and The Playhouse.

Bars and pubs too will be filled with music lovers, while a central feature of the festival is the scale of free events.

Brass bands will roam the city's streets, al fresco jazz hosted in the craft Village, while Guildhall Square's Gay McIntyre stage will host open air jazz for the next three days.