Easter Sunday: a day of resurrection. As I flew over the sun-baked plains and grass-roofed huts of southern Sudan, it seemed very far from our festival of chocolate eggs. I realised I was flying over a world of death - a civil war that has seen two million killed - and yet of a kind of birth, for Sudan has the fastest-growing Christian Church anywhere. A Biblical world of poverty, dust and palm trees.

Today was Captain Guy Brooking's first flight to the remote village of Liethnom. The airstrip was hard to see, and at a thousand feet above ground level we were both squinting into the fawn haze. Then I saw it, a narrow dirt clearing, and Guy made a low pass to check for potholes or wandering cows. He banked steeply, and brought the nine-seat Cessna Caravan grumbling towards earth.

Caravan: it's ironic that this is a place where that idea still strikes fear into people. A hundred and fifty years ago, before British colonial rule abolished slavery, the Dinka tribespeople, when they wanted to chide their children, would tell them: 'The camels are coming to take you away!' And almost 50 years after independence, the caravans are back, Arab raiders again carrying people off to work as slaves in the North. In Islamic Sudan, divided almost equally between Arab North and black South, but dominated by a Muslim regime in Khartoum, it is hard to escape the conclusion that slavery is state-sponsored.

Our airborne Caravan was carrying Kenyan members of World Relief - an aid organisation that has set up a dispensary in the village - three American teachers, and me in the co-pilot's seat, wearing borrowed epaulettes and dreaming that an unforeseen disaster would require me to fly the plane to safety. Happily for all concerned, there was no such disaster; Guy landed deftly, then flew away. Surrounded by 30 children chanting 'Welcome, Alison,' (none of us was called Alison) we entered the village.

I was installed in a small circular tukol built of mud bricks with a grass roof. An air of unease prevailed. Liethnom is not far from the front line - government Antonovs have twice bombed this insignificant hamlet, peppering it with craters.

The Nairobi representatives of the militia that controls this area, the Sudan People's Liberation Army, had issued me with a pass - but the local commander was sure to want to see me. Was I going to cause trouble?

World Relief's local programme manager was Stephen Kanyia, a man with a constant air of preoccupation. He spoke in a near-whisper. 'You must be discreet,' he told me. 'Frankly, I prefer you as a pilot to a journalist. Journalists bring problems, pilots are good guys. Try to keep a low profile.'

I visited a programme that is teaching the pastoral Dinka to plough, and observed the permanently radiant US missionary teachers training radiant Sudanese teachers about phonemes. The tukols rocked with Christian song - if this struggle is a jihad in the North, it's a Crusade in the South.

I did my best to keep a low profile. But one evening no fewer than seven men - community elders - came to see me. We sat in a ring with a watchful Stephen. One of the men, a commander, painted a vivid picture of the mess that is Sudan. He concluded: 'You, the colonial power, delivered the black, Christian South into the hands of the hostile Arab North. Surely if anyone has a responsibility to intervene here, it's Britain. When is Tony Blair going to speak out on behalf of the southern Sudanese?'

Eight sets of eyes regarded me keenly. I floundered. 'What can I say? 'We're totally in the wrong... Er, on behalf of Britain, I'd just like to say I'm very, very sorry.'

It was exactly what they wanted to hear. There was a palpable relaxation of tension - especially from the commander, who smiled genially, slapped my hand, and began to talk nostalgically of his happy days at Oxford.