Benton Park School in Rawdon, Leeds, is a well-disciplined, orderly place. When the pupils of Years 7, 8 and 9 file into the hall - about 700 of them - they create the archetypal school assembly scene, with rows of uniformed boys and girls facing the stage, overseen by teachers standing around the walls.
Then, into this bit of England comes Africa, or at least that bit of the continent which is the African Children's Choir - 20 boys and girls aged eight to 13 from Uganda, Kenya and Rwanda, singing, dancing and drumming their way on to Benton Park's assembly hall stage.
The concert is the closing highlight of Benton Park's multicultural week. Its pupils take a while to adjust their emotional antennae to what they are seeing and hearing, but gradually their reserve disappears, and they start to clap rhythmically. For their part, the African children just sock out the sound and movement. Their energy level belies the fact that they have just reached the end of a packed, month-long tour of West Yorkshire, having given dozens of concerts and workshops in halls, churches and schools across the region. "Everybody Has a Seed to Sow" they sing, as a member patrols the hall in a straw hat, throwing symbolic seed to the young people of Rawdon.
The choir is a big hit with all its audiences. Its repertoire places such Western crowd-pleasers as "Because You Loved Me" and "From a Distance" alongside traditional African songs and chants, in a range of languages. The children sing well, in that mid-range gutsy style that we associate with African choirs, and they look terrific in their colourful dress, with big smiles and an engaging way of swaying as they sing.
The African Children's Choir is now in its 15th year. As with all youth choirs, the membership changes continuously as young people move on and new singers join. Though it is clearly now a large community and team enterprise, the choir is the brainchild of Ray Barnett, an ordained Christian minister who has devoted most of his adult life to development work in eastern Europe and Africa.
It has been a particular pleasure for Ray Barnett that the West Yorkshire tour has focused so much on schools; the roots of his commitment to music as a life-enhancing force go back to his own school days just after the war in Ireland where he was born.
In his early schooling he was unhappy; he had learning difficulties that were misunderstood. Then, in senior school, he met a music teacher who worked with him at her home. "The kindness shown by that teacher set the stage for the rest of my life," he says.
In 1984, Ray was looking for a way of bringing to the world's attention the horrors of post-Amin Uganda, where thousands of orphaned children were wandering and dying on the country's savannah plateau. At that time, though, there were other tugs on the public's heartstrings and purse strings.
"It was the year of Band Aid, with the focus on Ethiopia," he says. "I had to find a different way of doing it." That was when he remembered giving a lift to an African child in the Sudan. "He sang every bit of the way, and it gave me the idea for a choir that would travel and raise funds."
The extra ingredient here, which appealed instantly to Ray, was that the choir would present a positive image of African people. "So often on television we see endless lines of starving children. My understanding of African children is quite different. They are bright and articulate, the most eager children for learning that I have ever met. That was the message I wanted to get across."
And that, without doubt, is the message the choir brings. Many members can tell horrific stories of abandonment, bereavement, homelessness and loss: Moses, who was infested with parasitic worms when he was rescued from the bush; eight-year-old Delphine, who was pulled alive from her parents' grave. The concert programme tells these stories, but on stage there is nothing but joy, energy and vibrant singing. This choir is the most impressive example of triumph over adversity imaginable.
West Yorkshire fell in love with these children. The organisers expected 10,000 people to attend the various concerts, but by the end of the tour they had sung to 22,000. Ashley Peatfield of BBC Radio Leeds, one of the leading organisers of the visit, says: "The children are completely inspirational. It's difficult to relate to people just how powerful they are, not just in their singing but in all that they stand for."