Nairobi Letter: A cloud of dust sweeps across a soccer pitch in Nairobi's slums as an 8,000-strong crowd sways one way, then the other, raising their hands in the air as one.
The Revival Flames, a gospel band, is reaching a climax on a podium before them. As the chords die away, a middle-aged balding American preacher, arrives on stage bringing his "Great Gospel Crusade" to Dandora, one of Kenya's most impoverished corners.
The sun is setting spreading a magical air across the faithful as Loren Davis welcomes them: "Hallelujah, we can feel the Lord here today." Some 8,000 mouths ululate in unison in a scene that will be played out across the city's soccer pitches and car parks many times over this week, as Nairobi plays host to evangelical preachers from the US, Europe and the rest of Africa.
Today's is a relatively modest gathering. Last summer, Juanita B Weeks brought 200,000 people to Uhuru Park in the middle of the city, bringing businesses all around to a halt. The influx of Western preachers, however, and the rapid growth of evangelical churches in Africa have alarmed some local theologians and international observers who see it as a new form of cultural imperialism.
Jesse Mugambi, professor of religious studies at Nairobi University, says American evangelists have filled a space left by the old European colonial powers since African nations won independence in the 1960s. "The British are no longer here in Kenya," he said. "Instead the Americans are ruling now and we have all these charismatic and Pentecostal groups from the American midwest and the south. But at the end of the day it is an integral part of the same package of imperialism."
This is a "fast food" version of religion, he says, riding roughshod over African values in favour of an ad-hoc selection of quick-fix theologies that can change from week to week.
"None of the tourist-evangelists from Europe and North America has publicly expressed any appreciation of the African culture and religious heritage," he argues in a recent paper published in Charismatic Renewal in Africa, a booklet designed to meet the challenge of the new movements.
"All of them condemn African culture and condone their own, creating the erroneous impression that Christianity and the Euro-American civilisation are interchangeable."
The road to Dandora leads past dozens of rickety shacks and tents that house the faithful of many flocks. Signs proclaiming the Maximum Miracle Church, Amazing Grace Worship Centre and the Redeemed Gospel Church battle for space.
Statistics are hard to come by but the World Christian Encyclopaedia, compiled by the Centre for the Study of Global Christianity in South Hamilton, Massachusetts, estimates that the number of people calling themselves born-again Christians in Africa has increased from 17 million in 1970 to 125 million today - about one-fifth of all Africans.
Jonathan Bonk, editor of the International Bulletin of Missionary Research, estimates that more that 1,400 new denominations are established in Africa each month. He is sceptical of critics who compare evangelists with colonial powers.
"The Bible resonates with Africa because it has a lot of blood and gore which resonates with African traditional religion which tends to be based on sacrifice and blood," he says.
"So there is a sense in which many of the texts that we in the west tend to find awkward really make a lot of sense to them."
Visiting preachers are drawn to Africa, he adds, because of the size of crowds they can attract. As congregations decline in western Europe and North America, evangelists can associate themselves with an energetic movement and demonstrate their prowess before vast audiences. In many ways the relationship is symbiotic. Some crusades are linked with medical clinics or emergency aid programmes.
When Bishop TD Jakes arrived in Nairobi from Texas last September, he brought a team of American doctors who ran free clinics and organised volunteers to dig wells. The aid work ended with two days of prayer meetings in the centre of Nairobi.
Then there is another reason for the influx of visiting evangelists, often linked with right-wing conservative movements, according to Prof Mugambi. He says the region is being carved up once again, just as it was during the scramble for Africa, when European powers divided the continent between themselves. Prof Mugambi explains: "At that time it was a battle between freedom and communism. Now that communism is no longer around, there must be a new enemy. Many of these evangelical groups are part and parcel of this new world order and see the new enemy as Islam."
That doesn't matter in Dandora where the crowd stands in darkness, transfixed as Davis paces from side to side of the stage booming out the story of Jericho's walls being brought low. The mesh fence that surrounds the soccer pitch is lined with hundreds more latecomers drawn by the music and lights. At the rear, Irene Nduku, who is 20 and unemployed but dressed smartly for this part of town in a two-piece suit, speaks for many when she explains why she came.
"We have heard good things about his version of the teachings," she says. "We heard that he survived a plane crash last year so it seems as if God is favouring him. We want to hear what he has to say and see if he will help us."