For the past six decades, North Korean music lovers have had little to sing about. Like everything else in that dark and shuttered country, music is part of the system of communist oppression presided over by Kim Jong Il: “Dear Leader”, tyrant and, inevitably, musical expert.

Mr Kim is said to compose his own music, of a spectacularly dreary and self-idolising sort. Back in 1968 he set down the inviolable principles of North Korean music: there should be no “uproarious Western music”, but only “lively and militant marches” celebrating his father, Kim Il Sung.

The last concert that Kim Jong Il attended included such catchy hits as No Motherland without You, with the lyrics: “Even if the world changes hundreds of times, people believe in you, Comrade Kim Jong Il! We cannot live without you.”

Then, last week, the world of North Korean music suddenly changed; and so, in a small but important way, did North Korea. The concert in Pyongyang given by the New York Philharmonic Orchestra marked the first time an important American cultural institution has visited the state since the Korean War. The orchestra played Gershwin and Dvorák, but also The Star-Spangled Banner and Arirang, a Korean folk song popular in both Koreas. The concert was broadcast live on state radio and television.

Now the North Korean authorities have gone a step further, by inviting Eric Clapton to give a concert in Pyongyang - the first Western rock star ever to receive such an invitation. Kim Jong Chol, Mr Kim's Swiss-educated son, is apparently a big Clapton fan.

By the standards of North Korean music, this is nothing short of revolutionary: From No Motherland without You to Star Spangled Banner to Slowhand in under a week.

Kim Jong Il could easily switch the music off again. He did not appear at the New York Philharmonic concert, and news of the event was relegated to a small item on page four of the official newspaper. It will take more than an Eric Clapton gig to

turn back decades of oppression.

Yet the small signs of a new musical openness in North Korea may be the first notes of an altogether more major change of key, and evidence that music and culture can move politics when diplomacy is otherwise deaf.

Music has often been deployed for diplomatic purposes, with varying success. In the Second World War there were some classical music skirmishes on the sidelines: Britain dispatched Malcolm Sargent - “the ambassador with a baton” - to make music in neutral countries, and Germany did the same with the conductors Wilhelm Furtwängler and Herbert von Karajan. When Von Karajan met Sargent met during rival tours, he is said to have told his British competitor: “When the Führer gets to London, you will be shot.”

The Cold War too had its own peculiar musical accompaniment. In 1956, just three years after Stalin's death, the Boston Symphony Orchestra became the first big American ensemble to tour the Soviet Union, playing to packed houses and huge acclaim, political and musical. “We could not have better spokesmen than these musicians,” declared The New York Times.

The long process of opening up relations with China involved panda diplomacy and ping-pong diplomacy, but also philharmonic diplomacy: the Philadelphia Orchestra was the first to tour communist China in 1973, shortly after Richard Nixon's history-changing visit.

Sometimes the music fell on deaf ears. “I am not a jazz fan,” Nikita Khrushchev told the clarinettist Benny Goodman during his 1962 visit to the Soviet Union. “I don't understand jazz. I don't mean just yours. I don't even understand our own.” Just two months after the Boston Symphony Orchestra went home in 1956, with Soviet plaudits ringing in their ears, the Hungarian revolution was brutally crushed by Soviet forces.

Music does not change politics, but a shared cultural understanding can blunt political hostility. At the very least, it provides a shorthand more comprehensible than diplomatic language. The new Russian president-elect, Dmitri Medvedev, has been pictured beaming alongside the members of Deep Purple after their concert at the Kremlin last month. Medvedev makes much of his rock-fan credentials, citing a lifelong devotion to Pink Floyd, Led Zeppelin and Black Sabbath. A talent for playing Stairway to Heaven on air-guitar may not necessarily indicate a liberal pro-Western stance, but it's a start.

Medvedev's memories of secretly copying heavy metal tracks as a youth are intended to send a message, for the freedom to listen is a subtle sort of subversion. Tyrants have often sought to control the soundtrack. The Nazis prohibited “degenerate” music; Algerian Islamists killed musicians regardless of type; when the Afghan Taleban came to power in 1996, all music, and all musical instruments, were banned, the music sellers in the markets were beaten up, their cassette tapes disembowelled and the tapes festooned from lampposts.

The first signs of liberty in Afghanistan came when the bazaars rang again to a cacophony of Indian, Iranian, Western and traditional Afghan music. Free music is revolutionary. Verdi's operas were the rallying anthems to Italian unification. During his long rebellion, Václav Havel secretly listened to Lou Reed.

The people of North Korea are used to hearing the folk song Arirang, because every year the communist authorities hold a festival at which 100,000 people perform calisthenics to the tune, in another mass obeisance before Kim Jong Il. Last week North Koreans finally heard it played by a free orchestra.

The first strains of freedom have been heard in one of the least free countries on Earth. North Korea's State Orchestra is planning two concerts in Britain this year. Clapton will play Pyongyang in 2009. North Korea and the West are still not talking the same language; but under our breath, we may be humming the same song.

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