"Ptoot-ptoot!." Hugh Masekela is performing "Coal Train (Stimela)," and he's as close to mimicking a train's whistle as is humanly possible. And the audience at London's Barbican Centre is loving it. A mixed bag of Africans and Europeans have come to hear the legendary South African flugel horn and cornet player collaborate with a group of musicians from different corners of the world. including London's Soweto Kinch, Yaron Herman, an Israeli pianist now based in Paris, Sonti Mndebele, a singer who has performed with Masekela before, most famously in the collaboration with Paul Simon on Graceland, and Ghana-born keyboardist Kwame Yeboah, much in demand with the likes of Craig David and Stevie Wonder.

But is this, as the advertising describes it, jazz? It sounds closer to the Afro Beat of Fela Kuti. The audience is unconcerned by such questions and as he breaks into "Bring Him Back Home", his hit single which was adopted as an anthem in the campaign to free Nelson Mandela, they rise to their feet and, despite protestations from health and safety-minded stewards, begin to dance.

At a discussion forum the following day at the Greater London Authority's building beside the Thames, the need to define jazz seems to be on everyone's mind. Francesco Martinelli, a writer and academic specialising in jazz history at Istanbul's Bilgi University, described it as "at its best inclusive" while suggesting that the concept of pure jazz- the image of dark, smoky clubs, skipping cymbals and freeform saxophone solos- is a contradiction in terms for, as he points out, jazz grew out of the cultural melee of African, European and Creole influences that comprised New Orleans' culture at the beginning of the 20th century. Since then it has spread out across America and travelled back across the Atlantic to its roots and planted itself in Paris, Budapest, London, Amsterdam and Scandinavia and developed distinct styles in each of these places.

Hugh Masekela's concert at the Barbican and the discussion forum at the GLA were part of A Jazz Odyssey; Music & Migration a series of events devised and organised by the music promoters Serious in collaboration with Banlieues Bleues in the Paris suburbs and A38 in Budapest, to explore how migration has enriched European culture and how music, and in particular jazz, can act as the agent that brings diverging cultures together. Along with the issue of definitions (not just of jazz but also of 'world music' with which much of the music coming from outside of America and Europe often is confused) other questions raised and discussed were to what extent jazz has been influenced by the migration of musicians across borders and to what extent migration has been propelled by music's need to explore and digest new cultures: could the emergence of gypsy jazz inventor Django Reinhardt have occurred without an influx of jazz musicians from America to Europe's capitals? Could Don Cherry's music have been so richly diverse, taking in influences from the UK punk scene, traditional Turkish music, and India and Africa too, if he had not travelled so extensively?

A Jazz Odyssey sought to debate these questions and also to see if it is possible to measure music's capacity as a cohesive tool that brings cultures together and one that can even inform social policy. In Britain, the existence of government agencies such as the Arts Council would certainly suggest that politicians recognise the value of culture in generating social change. But, as many pointed out at the discussion forum, the distinction between high art and art funded for social change can be measured in terms of finance; the fact that 'high art' projects receive so much more funding suggests that socio-cultural projects still have a long way to travel before they are accorded the value that many believe they deserve.

Kinetika, an Arts Council-funded project that works with local communities in London teaching carnival skills to school children, illustrates just how effective the merging of music with social policy can be. With performances at the Thames Festival, the London Jazz Festival, and the Notting Hill Carnival, the organisation has now introduced a whole generation of London's schoolchildren to the benefits to be gained from performing; four participants at the discussion forum explained how the project had not only opened them up to a whole new world of musical influences but that performing had also given them a sense of confidence that they could apply to other areas of their lives.

On a more academic level, Ulrika Hanna Meinhof, Professor of German and Cultural Studies at Southampton University, has been conducting a pan-European study (www.citynexus.com) on how migrant communities in European cities can act as agents that further diversify the development of music. If musicians today can be seen as the world's nomads, with concert tours as their need to find new pastures, then migrant artists, with their links not only to their country of origin and their country of residence but also to ethnic communities across borders, are best disposed to disperse seeds of understanding in a rapidly changing world.

The most significant distinction between music and politics is that music forces you to listen and with performances and discussions in the heart of the Paris banlieus, where of late racial tension has shown itself to be so fraught, and in Hungary, on the edge of the European Union's new frontier, A Jazz Odyssey is a timely effort to promote intercultural understanding. It is jazz, with its roots so firmly connected with migration and collaboration that is best qualified to expound these ideas. Hugh Masakela's performance at the Barbican was a practical demonstration of how jazz can fuse a milieu of diverging influences and cultures into a rousing and unifying experience. "Bring Him Back Home" was the stirring finale to his concert at the Barbican and the appearance of all his collaborators on stage simultaneously best encapsulated Jazz Odyssey's theme. Can music change the world? Perhaps. Perhaps not. But if it gets you to dance it has made a start.