Glyndebourne survived the Second World War by opening its doors to evacuees from east London

The opera venue's act will be honoured at this year's festival reports Jessica Duchen.

An English country house; a rarefied ivory tower in which to explore high art; the performance of tragedy and comedy alike; dinner al fresco; and that's just on stage.

Glyndebourne Festival Opera – famous for top-notch performances in a sumptuous East Sussex setting, complete with picnics – is opening its 2013 season with a new production of Richard Strauss's Ariadne auf Naxos, the first half of which concerns precisely such a situation.

Nevertheless, the concept dreamed up for it by the young German director Katharina Thoma feels close to home for another reason. It was inspired by the Second World War transformation of Glyndebourne itself into a centre for evacuees from east London.

When the floorboards of Glyndebourne's Old Green Room – a panelled gallery in the Christie family's manor house – were taken up for refurbishment in the early 1990s, they revealed an unexpected treasure-trove.

Down the cracks between the boards had fallen layer upon layer of playing cards, greeting cards and little lead toy soldiers. This was a legacy of the time when, following the outbreak of war in 1939, Glyndebourne had hosted a hundred evacuated children aged between one and six.

Archive photographs show the Old Green Room as a dormitory filled with rows of small beds with the Christie children's nursery transformed into a sick bay, complete with uniformed nurses and the tiny newcomers playing in the gardens, patting lambs on the farm and discovering that milk comes from cows, not bottles.

Glyndebourne's archivist, Julia Aries, explains that the estate manager had seen which way the wind was blowing. "He didn't want Glyndebourne to be taken over by the Ministry of Defence and trashed," she says, "so he put it forward as an evacuee centre. Then, on the 'false start' of the war, they promptly shipped 300 babies and 72 carers down here." The estate could not cope with such a massive influx and the story goes that Rudolf Bing, the opera festival's general manager, had to rush into nearby Lewes to buy up every available potty.

Eventually, the numbers settled to a third of the first rush, and country life with play-based learning and plenty of fresh air began for Glyndebourne's new inhabitants, under the direction of a matron, who, in a somewhat unfortunate choice, termed herself the Commandant. The cook was able to amplify food rations with rabbits from the fields and eggs from the farm, and, supplied with drums of Klim powdered milk by some Canadian soldiers who were billeted in nearby Firle Place, she created makeshift ice-cream to give the little ones a treat.

Official photographs, mainly taken in summer, made the children's existence look idyllic, but there is no doubt that some had been traumatised by their experiences in London or by being removed from their families. A newspaper clipping describes "one child who had refused up till then to open his mouth or make friends turned scarlet with ecstasy when he found himself clasping a lamb, and was happy and normal from that day".

The opera and the family fared less well. The former ceased to function in 1940 and the company scattered. The music director Fritz Busch and artistic director Carl Ebert, who were both refugees from Nazi Germany, headed respectively to Buenos Aires and Turkey. Audrey Mildmay, Lady Christie, who was herself a well-known opera singer, took her two children to Canada for safety. Sir John Christie stayed behind, listening to his wife's voice on gramophone records. He was all too aware of the irony that his house was filled with children while his own were 3,000 miles away.

Katharina Thoma, who won second prize in the European Opera Competition Camerata Nuova in 2007, visited Glyndebourne for the first time in spring 2009, after the company's general manager David Pickard and music director Vladimir Jurowski suggested that she could direct Ariadne auf Naxos there as her UK debut. The trip sowed the seeds of an idea for the production. She has updated Ariadne's setting to – well, an English country house in the 1940s.

In the story, which the writer Hugo von Hofmannsthal crafted as librettist for Strauss, our hero is the Composer, a youth creating his first serious opera on the myth of the god Bacchus rescuing Ariadne from Naxos. He is desperately upset when instructed that his lofty work must be performed simultaneously with a competing comedy because of time pressures over dinner and fireworks. The second half shows us the Composer's opera and what happens when the comedy troupe, led by the virtuoso soubrette Zerbinetta, interrupts Ariadne's laments. But the opera transcends all its troubles, concluding with a sublime love duet for Ariadne and Bacchus.

"The idea of setting it in wartime came about because I felt that in the music there were more existential issues to worry over than the protagonists in the Prologue actually do," says Thoma. "If you listen to the end of the Prologue, when everything breaks down, it sounds like a major catastrophe."

Therefore, instead of serving as an opera-within-an-opera, the second part offers a continuity of narrative. The Composer, injured, observes the depressed and suicidal Ariadne from his hospital bed, the house having been transformed not into an evacuee centre but into a hospital treating the wounded from the Battle of Britain. "Observing her, trying to help her, and seeing what happens to her and Bacchus, he experiences a maturing process that leaves him better able to cope with the real world outside his ivory tower," Thoma suggests.

The Ariadne set designs by Julia Müer are based generically on English country houses of that time, but the closeness to Glyndebourne will probably be self-evident. Thoma arrived there in April and has been staying in the house, as the creative team usually does during rehearsals. "Every morning I wake up and think I am on the set of my opera," she remarks.

Learning about Glyndebourne's fortunes during the war, Thoma says she was impressed by the way that in Britain "turning a manor house into a hospital was a typical thing, because people needed each other and held together". It might seem risky for a German director to choose a wartime theme for her first UK production, but Thoma's generation can perhaps take a new perspective on those years.

"For me, it was fascinating to see how British people have dealt with the subject in the past and still do," she says. "They seem very open and positive." She viewed a documentary in which individuals who were in their twenties during the war described it as the happiest time of their lives: "That seemed astonishing to me, but I think it must in certain ways have been a great experience to go through this endurance, because they shared their hope and their strength and they overcame it together."

Ariadne auf Naxos launches a delicious summer for Glyndebourne, which also includes works ranging from Rameau's Hippolyte et Aricie to Britten's Billy Budd. The festival is aiming to make access more of a priority than ever before, screening all the productions in cinemas and online.

But this year also marks the end of an era: it is Vladimir Jurowski's last season as music director, a post he has held since 2001. He wields the baton for Richard Strauss ahead of the 150th anniversary of the composer's birth next year, when the young British conductor Robin Ticciati takes over. If the new Ariadne auf Naxos highlights the atmosphere of changing times, perhaps that is no coincidence.

'Ariadne auf Naxos', Glyndebourne Festival Opera (01273 813813) 18 May to 11 July