Cornbury Festival has always prided itself on its niceness. Its blend of family-friendly fun, country house setting, well-heeled clientele, unthreatening atmosphere and celebrity punters have earned it the nickname ‘Poshstock’.

But its chilled Champagne and Pimms bars, fenced off VIP areas, preponderance of Hunter wellies and a car park stuffed with shiny black 4x4s, belies an element of coolness , which comes from not trying too hard.

“You could say we are so uncool we are cool,” laughs Hugh Phillimore, who set up the festival 15 years ago and is still the driving force behind the event which springs into life at Great Tew Park, near Chipping Norton tomorrow.

“More than 75 per cent of the audience are regulars and part of the reason they keep coming back is that it’s the same – we are reassuringly familiar.

“After our grand finale last year, a lot of people asked me to bring it back, which we have.

“I didn’t like it at first when it was first referred to as ‘Poshstock’, but if that means it is safe, nice and well run, then I can live with that.”

Despite being a haunt of the local Chipping Norton set, with the likes of David and Sam Cameron, Jeremy Clarkson and former Sun and News of the World editor Rebekah Brooks regularly spotted, along with celebrity Cotswold farmers Adam Henson from Countryfile and Alex James from Blur, things have rarely run smoothly.

The festival, which began life at Cornbury Park, near Charlbury, has hosted such stars as Paul Simon, Van Morrison, Robert Plant, Blondie, Bryan Ferry, Tom Jones, Elvis Costello and Martha Reeves, as well as sets by a number of musical legends no longer with us, such as Amy Winehouse, Joe Cocker and Humphrey Lyttleton. However, it has repeatedly struggled to turn a profit.

In its second year it lost £500,000, and Mr Phillimore had to put his house up for sale. He has regularly recorded a thumping losses after the event, the festival only going into the black on its 10th anniversary in 2013 and last year – which was billed as its finale.

In the event, the festival, headlined by Bryan Adams, Jools Holland and the Kaiser Chiefs, proved such a storming success, that with the smoke only just clearing from the farewell firework display, Hugh was persuaded to resurrect it.

Its enduring popularity is down to its easy-going nature, family vibe and an ever-changing eclectic line-up which appeals to everyone from glittery teenage pop-lovers and picnic blanket-toting parents to beard-stroking country, rock and blues fans.

This year’s headliners are UB40 tomorrow, Alanis Morissette on Saturday and Squeeze closing things on Sunday.

The rest of the bill offers plenty of treats too though, with ska and reggae icon Jimmy Cliff, 90s dance-crossover act Stereo MCs, Lukas Nelson (son of country legend Willie) and country-rockers Danny & The Champions of the World tomorrow, a female-led line-up on Saturday with Mavis Staples, Amy Macdonald, Nina Nesbitt, Pixie Lott, PP Arnold, Grainne Duffy and reality TV star Megan McKenna.

Sunday’s bill features Mark Cohn, Mari Wilson, Staks soul, Lissie and 60s pin-up Andy Fairweather Low of the band Amen Corner (best known for belting out hits If Paradise Is Half as Nice and Wide Eyed and Legless). And that’s barely scratching the surface.

There is also a top-notch comedy tent with some giants of the live circuit, among them James Acaster, Katy Brand, Phil Wang, Felicity Ward, Ivo Graham, Suzi Ruffell and Vicar of Dibley writer Paul Mayhew Archer, who lives in Abingdon.

“I’m really excited,” says Hugh. “We’ve got some great names.

“Alanis played her first UK gig on Saturday and was fantastic. I’m very interested to see Jimmy Cliff, I’m a big fan of Mavis Staples, Stereo MCs are still rocking and Lukas Nelson is amazing. He is Willie Nelson’s son and plays with Neil Young’s studio and live band so will be really rocking!

“I’m a fan of Amy’s too so am happy to have her back there.

“Deacon Blue and UB40 are very popular and Squeeze are on their way to acquiring national treasure-status.”

Among the surprises is an appearance by Peter Asher – half of the 60s duo Peter and Gordon who scored a hit with Paul McCartney’s A World Without Love – getting to know the young Beatle as he went out with his sister Jane Asher.

He went on to become a famous record producer and manager for acts including James Taylor – which is how Hugh met him.

“He’s an amazing character with some incredible stories,” smiles Hugh. “And he was the inspiration for Austin Powers.

“I had breakfast with him in LA and was completely silent as he wheeled off all these amazing tales.”

Other eyebrow-raisers are a show by Si King from The Hairy Bikers, who takes to the stage in the Campsite bar with his rock covers band – as well as serving up banquets to punters from a wood burning oven with his partner in crime Dave Myers.

Then there is country singer Megan McKenna – who made her name on reality TV shows Ex on the Beach, The Only Way is Essex and Celebrity Big Brother. “I just thought she was a good country singer,” says Hugh.

“I had no idea she was such a big star, but then I don’t watch any of those shows.”

More than anything though, Hugh is looking forward to welcoming back the many friends he has made over the years – many of whom bombarded him with requests to resurrect the festival.

“As last year was supposed to be the last we got rid of all the furniture and gave away or burnt everything. Even most of the team is new.

“But bringing it back was the right thing to do. Last year was one of the first times I didn’t lose shed loads of money but I also realised I was going to lose touch with hundreds of people I see regularly here and love hanging out with. So I’ll keep going for as long as I’m still standing!”

And he is hoping the current heatwave continues. “Of all things, the heat is a nice problem to have but we do have to be careful,” he says. “We don’t want people getting sunburn or roasting. The site is very dry but beautiful.”

Cornbury Festival runs from tomorrow to Sunday at Great Tew Park, near Chipping Norton.
Tickets from cornburyfestival.com