UP to 20,000 folk-rock fans will today start arriving at the county’s longest-running festival — continuing a ritual which has continued since the hazy 1970s.

With tankards clipped to belts, penny whistles in pockets and guitars slung over backs, they will pitch-up in a usually sleepy north Oxfordshire village — the name of which has become synonymous with this annual gathering of the tribes — Cropredy.

Founded, and still run, by the band Fairport Convention, the event is one of the festival-world’s greatest survivors – with punters coming back year after year for a heady mix of real ale, banter and good music.

Whatever you do though, do not call Fairport’s Cropredy Convention a folk festival.

“It is more than that,” says festival director Gareth Williams, who organises the event with Fairport members Simon Nicol and Dave Pegg.

“It may tug a respectful forelock to the folk-rock tradition, but it is a music festival.

“And the line-up is great — with 22 artists, and something for everyone.”

And he’s right. While Fairport headline the Saturday, the rest of the bill is more diverse than ever. Tonight’s line-up features big-band folk-punks Bellowhead and is headlined by 1980s pop act Squeeze, tomorrow features Ireland’s Saw Doctors and singer songwriter Joan Armatrading, while Saturday boasts Dr Hook’s Dennis Locorriere, and another ’80s pop sensation Big Country.

“There are plenty of young bands, too,” says Gareth. “We have Ellen and the Escapades, Brother & Bones and BBC Young Folk Award winners, Ioscaid, who are fabulous. They could all be the highlights of the festival.

“There’s something about Cropredy, that the big hit of the festival is often someone you’ve never seen before.”

But it is Fairport Convention, and the band’s former members, who will remain the big draw — particularly in this, their 45th anniversary year. The band effectively book-end the festival — opening with an acoustic set today and rounding off with their customary three-hour closing show on Saturday.

Founder member Richard Thompson, widely regarded as one of the world’s best guitarists, plays tomorrow (Friday), while vintage Fairporters Ashley Hutchings, Dave Swarbrick, Dave Mattacks, Jerry Donahue and Martin Allcock will also be playing over the weekend. As will some of their children — among them Kami Thompson and Kristina Donahue and Ashley Hutchings’ son Blair Dunlop.

“Fairport put their name to the festival so it’s only fair they welcome people to it — which they will do at 4pm,” says Gareth. “There will also be a very crowded stage for their closing set. Oh, and Richard has a few surprises of his own.”

And Gareth is confident the festival will be a success — with slightly lower ticket sales buoyed over the weekend by a good walk-up from local people.

“We are not immune to the things which have hit other festivals,” he says. The weather is the single most important factor — and it has been dire, though the site is in good shape. But we have had people say they would love to come but are volunteering or have tickets to the Olympics, and are missing the festival for the first time in 30 years.”

He adds: “People who live close by will leave it to the last minute so they can look to the skies and see what the weather is doing — like I would. But I am sure they will come. And they will all be able to buy a ticket on the gate.”

So what is it that keeps people coming back year after year?

“If I knew the secret, I’d bottle it and make millions,” says Gareth.

“It has grown up from a small event on a village green and now covers 176 acres of farmland. It was not created with that in mind.

“The festival as it is now was not part of the plan when Fairport decided to get a few mates together on the lawn all those years ago. But it has survived.

“We have a loyal following. People come year after year; and they consider it their festival. It is part of their calendar.

“It’s due to its family atmosphere and, of course, Fairport themselves — who are always available to their fans — and can usually be found at the festival bar talking to them.

“It’s going to be a lovely weekend — and the only place to be.”

Fairport’s Cropredy Convention runs from today to Saturday, north of Banbury. The festival offers three-day (Thursday, Friday and Saturday), two-day (Friday and Saturday), and Saturday-only tickets, costing £110, £100 and £80 respectively. Camping passes are extra. All are available on the gate. Go to fairportconvention.com