Lady Rotherwick is at home in the Wilderness

Cornbury Park. It’s one of our finest stately homes, the haunt of peacock, deer, sheep and, this weekend, a 20,000-strong crowd of musicians, actors, acrobats, chefs, dancers and lively festival-goers.

And while the wildlife may be ambivalent, the owners of the 17th-century country house in the heart of the Oxfordshire Cotswolds couldn’t be more delighted. Far from hunkering down behind the high walls of their estate, Lord and Lady Rotherwick are keen to share this slice of rural heaven with the public, and can’t wait to join them at the country’s most eclectic and freewheeling festival: Wilderness.

“I am super excited,” says Lady Rotherwick. “I can’t believe that after all the build-up it’s come round again.”

Lady Rotherwick is the driving force behind the decision to use the park as a festival venue. For seven years it hosted the eponymous Cornbury Festival, but, when that went into liquidation, the Rotherwicks seized the opportunity to do something different, opening their gates to the team behind the successful Secret Garden Party and Lovebox festivals.

While Cornbury Festival continues, on a new site at nearby Great Tew Park, Wilderness, which is now in its third year, is an altogether different animal. Instead of Pimm’s bars, roped-off VIP areas and celebrity guests, Wilderness is a more organic and creative event, with performance spaces designed around the estate’s rugged valleys and ancient woodland.

And just as Wilderness is far from the average music festival, Tania Rotherwick is an unlikely Lady of the Manor. A slim, athletic music-lover with a ready smile, she is equally at home in the boisterous crowd in front of the stage as in the big house which overlooks it.

And, as a festival aficionado, she is particularly delighted with this year’s line-up, headlined by Australian synth-pop duo Empire of the Sun, folk-pop band Noah and the Whale and American singer-songwriter Sixto Díaz Rodríguez.

Also playing are West London country-rockers Treetop Flyers, indie-rock five-piece Tribes, Isle of Wight pop act The Bees, London electro artist Ghostpoet, Brit award-winner Tom Odell, Canadian singer-songwriter Martha Wainwright (sister of Rufus), soul artist Michael Kiwanuka, Australian singer-songwriter Matt Corby, young indie-folk musician Lucy Rose, and the London Folk Guild.

“The music is particularly strong compared to previous years, when it was only a small part of the festival,” she says. “I love all the acts, listen to a lot of them incessantly, and can’t wait to see them. The only frustrating thing is getting to the end of the weekend and realising all the other things we didn’t get to do. I don’t want to pack in so much I’m running around like a headless chicken.

“There is simply too much going on. The only way to do it is to split yourself into four — and it’s worth staying up into the night. I do, and my mother, who is soon to turn 80, will also be rocking along.”

Other than live music, there are performances by visiting theatre groups, including Shakespeare’s Globe, Petersham Playhouse and the Unicorn Theatre, shows by Vignette Opera and English National Ballet, fancy dress balls and displays of acrobatics and street theatre from Transe Express and Les Pepones.

Then there are mind-expanding pursuits: art and craft workshops and talks hosted by The Huffington Post, School of Life, Intelligence Squared, Royal Observatory and The Idler magazine. Foodies, meanwhile, will be treated to tented banquets from top chefs Yotam Ottolenghi, Russell Norman of London restaurant Polpo, and Mark Hix. Hungry festival-goers will also be invited to tuck into first-class meat and offal dishes at the St John Dining Room, Moorish fare in the Moro souk tent or try their own hand at the Thyme Cookery School.

And, if revellers find themselves inspired by their surroundings, they can join woodland walks, wild swimming and horse riding — before relaxing in the spa.

While this year’s 20,000-capacity festival is a sell-out, both Lady Rotherwick and festival director Tim Harvey have resisted the urge to expand, preferring to preserve the intimate atmosphere and sense of surprise which comes from not crowding the site.

“We have done particularly well in year three to attract 20,000 people,” she says. “But we didn’t want to make it any bigger at this stage.

“The reviews have been fantastic and its success is all down to the feelings of those who have been and want to come again. Last year’s was such a good event and the weather was perfect. It will be difficult to surpass, but I think we will.

“I really look forward to it,” she adds. “I have got hundreds of people camping on my lawn and the house will be chock-a-block.”

Among those enjoying themselves will be her children, fans of the festival’s Bushcraft workshops, and who, she says “absolutely love” having a festival on their doorstep.

“It creates fabulous memories for the children,” she adds.

Don’t be too surprised if guests also include the new governor of the Bank of England. Canadian Mark Carney is married to Lady Rotherwick’s sister, Diana Fox Carney.

Fun it may well be, although surely, come Monday, she will be relieved to see the crowds disappear from her ‘backyard’ and returned to the deer and peacocks? “It’s the opposite,” she laughs. “We’d be happy to have this for a full week. Every last second is enjoyable, and it’s a real pleasure and the nicest way to see people.

“The site has all come together well, now we are just waiting for it to start. It’s going to be a good one.

“Wilderness is so amazing that you can go and have a great time — even if you live here all year round!”

• Wilderness Festival Cornbury Park Starts today, ends Sunday Tickets are sold out Visit wildernessfestival.com