Did an orchestra lure North Korea to the negotiating table? In February, the New York Philharmonic played a unique concert in the North Korean capital, Pyongyang, televised around the world. Four months later, the secretive government handed over details of its nuclear programme, kick-starting stalled international discussions. Should the NY Phil take the credit? Well, no. But, twinkles the orchestra’s president, Zarin Mehta, “I would’ve loved to have been in the talks after the concert, to see the difference in atmosphere”.

We’re talking cultural diplomacy - the idea that the arts can play a decisive part in international relations through winning hearts and minds. Once a plank of cold-war policy, it has lost currency of late; but, in an atmosphere of heightened sensitivities between the West and both Asia and the Middle East, perhaps its ability to build a rapport is needed again. When they tour, arts companies create a buzz of economic and political activity that can, it is argued, be productive way beyond art itself.

Late last month, I joined the Royal Ballet as it began a five-week tour of Asia. The stint in Beijing was the most significant, opening the Olympic cultural festival and inaugurating an ambitious partnership with the National Centre for the Performing Arts (NCPA) in Beijing. This startling building, known locally as the Egg, sits like a titanium spaceship close to Tiananmen Square: a reminder that, in China, shiny new affluence jostles with continuing anxieties about human rights. In one of the subterranean dressing rooms, I found Dame Monica Mason, artistic director of the RB. She remembers that, however strained a period, the cold war enabled cultural interchange, with ballet in the front line: “Its strength is that it is communication without words.” As a dancer, she toured with the RB to the segregated southern states of America, where black musicians had to travel separately from the rest of the company, and through grim eastern Europe. Soviet dancers would invite the visitors for a walk in the park (to avoid surveillance) to describe their lives and thank the company for coming – “Goose-bump time,” Mason says.

Unlike conventional diplomacy, cloistered behind closed doors, art works in the open, forging a direct connection with the spectators. Mason has tears in her eyes as she recalls taking Kenneth MacMillan’s Gloria, which is fuelled by the horror of conflict, to what was then Leningrad, where it conjured memories of the wartime siege. “These helmeted soldiers came over the blasted hill – and there was an audible [gasp]. At the end, they went mad. People were crying. They got it in one second. Later, people came up to us in the street and said, ‘Thank you for Gloria.’ ” Even more intimate connections can be fostered behind the scenes. In Beijing, the RB mounted a big education programme, aimed primarily at student teachers. Chinese participants fired questions at their visitors. The dance scholar Professor Ou Jian-ping marvelled at the British approach – the emphasis on teamwork, the unforced way in which they harnessed a hyperactive boy’s disruptive energy. Ou urged his students to attend: “I told them, ‘Grasp this chance, it may change your life.’ ” Of course, you have to get the art right and not pander to expectations. Damian Woetzel, who recently retired from New York City Ballet and is a vocal advocate of cultural diplomacy, says: “Safe art is not necessarily great art. Companies bear the responsibility of showing what we, as a nation, hold to be worthy art. It is vital that we aren’t guided in artistic decisions by the nonartistic.”

Cultural diplomacy is not purely altruistic. China, especially, with its voracious appetite for classical music, represents a vast, barely tapped market for western arts companies. “There are 30m registered piano students in China,” Mehta says, allowing a second for the figure sink in. This points towards the real prize for the RB: getting a foot in the door before the digital revolution really kicks off. Tony Hall, chief executive of the Royal Opera House, says that the touring presence opens a doorway for lucrative video on demand, live relays and webcasts. “It’s a global world,” he says, “and one or two companies will be brand leaders.” (The RB has a head start. Ou says: “People love the title ‘Royal’ Ballet. The word is gold.”) So, the most significant audience for The Sleeping Beauty was not the one inside the NCPA, but the millions watching it on Chinese television the next night. The company awaits viewing figures, but is confident this was the biggest audience in its history.

An event like the RB’s visit to the Egg creates a buzz. The ROH’s chairwoman, Dame Judith Mayhew Jonas, noted the presence of Chinese ministers at a reception held by the RB’s sponsor, Rio Tinto. The mining company, engaged in complex negotiations with China over the price of iron ore, had its own pressing reasons for luring dignitaries with dance and canapés. “If you have the right economic and cultural groups, you can cross-fertilise,” Mayhew Jonas says.

Everyone agrees that a big company serves as ambassador for both its art and its country. Mehta admits that hearing the American national anthem played in Pyongyang was “a hugely emotional experience”. And that a classical orchestra made front-page news around the world was good for music. But is it good for the artists? “It develops them as human beings,” Mehta says, while Woetzel insists that “all artists benefit from seeing their colleagues’ work”.

Sitting behind us at the RB’s Egg triple bill was a group I recognised as dancers from the National Ballet of China. At first, I thought they were not enjoying it - they muttered, quite loudly, through much of the performance. In fact, they were not dissing, but discussing, avidly. They cheered enthusiastically at the end of Wayne McGregor’s weird, twisty Chroma - could they have ever seen anything like it? - and went wild during the virtuosic classical divertissements. It was insanely exciting to witness these connections being made.

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