IT was a debt James McAvoy knew he had to honour.
A debt to Uganda, the chaotic little country that had lifted him to stardom, stolen his heart and stirred his conscience.
While filming Last King of Scotland on location in this benighted East African nation, he and his Oscar winning co-star Forest Whitaker had listened in horror as local actors told them of the nightmare in the north of the country.
For 21 years - long after the brutal dictatorship of Idi Amin - Uganda has been caught in bloody guerrilla war between government troops and the brutally bizarre Lord's Resistance Army.
Now, travelling with the British Red Cross, McAvoy has kept his promise to return to Uganda to help the people whose daily lives are blighted by the conflict.
Almost immediately, he was plunged into an African maelstrom of horror and human suffering.
Standing in a refugee camp among the smouldering remains of 70 homes, he finally understood the enormity of the tragedy that has hit this forgotten corner of the world.
The UN has described the conflict as the "world's most neglected crisis". McAvoy is more direct.
"It's f**ing purgatory," he says, surveying the devastation.
He had spent two and a half months on location in Uganda while making the film about Idi Amin.
While there, he experienced at first hand some of the problems affecting the Ugandan people.
One evening, he saw a woman, distressed beyond endurance, try to kill her baby by throwing it into the road. McAvoy still doesn't know whether the child survived as, despite his pleas, his driver said it was too dangerous to stop.
On this trip, he ventured into dangerous Acholiland in the north of the country, close to the Sudan border where people are dying as the result of the conflict.
Terrified for their lives, up to 1.7million have moved into desperately overcrowded camps where they live in cramped misery, seeking safety in numbers.
DISEASES like malaria are rife. Tens of thousands have HIV/AIDS with no access to the proper drugs.
Witchcraft is common in the camps and the rates of r*pe and alcoholism are distressingly high.
The risk of fire is ever-present because the tiny mud huts, with their grass thatched roofs, are just inches from each other.
McAvoy arrived at one camp just hours after fire had robbed the locals of what few comforts they had left.
"I was absolutely appalled when I saw what had happened," he said. "It was devastating. The place was still smoking, the walls were still hot. One guy told me he and other families were now being forced to sleep in the open.
"Seventy houses were lost. The fire spread very rapidly. People lost everything
"They are forced into a weird kind of f***king purgatory, there's no work, nothing to do but drink.
"The level of crime is shockingly high and the level of r*pe is worse. It's like hell." McAvoy, 27, who is married to actress Anne-Marie Duff and first shot to fame in TV series like Shameless and State Of Play, fell in love with Uganda during Last King of Scotland.
He had never met Forest Whitaker until the film but realised he was watching something special as the work went on.
"You never really dare to hope that it will be excessively successful, but while we were making it I could tell that Forest was giving a remarkable performance," he said.
While on location he and Whitaker had been shocked when they heard from Ugandan actors in the film.
Sam Okello, who played Bonny, is an Acholi tribesman who escaped from the North.
McAvoy said: "I had no idea this this awful violence was going on until 18 months ago when I did the film.
"While here on location I learned a hell of a lot about the state and welfare of the nation. Everybody was vocal because we were making a very political film, everyone was really open with their views and talking about Amin led on to discussions about the problems of Uganda today.
"It was a very politicised, intelligent debate during filming, in between scenes, and after dinner.
"I fell in love with Uganda - but a much safer, much happier part of Uganda.
"The country has made my career, Forest Whitaker's career, the director Kevin Macdonald's career. Every crew member and every cast member has had about three leg-ups the career ladder because of the film.
"We can't deny that and I suppose it's out of a sense of debt that I thought coming back like this might be a good thing to do.
"Ugandan people are really positive, but when you think about the adversity they face it's incredible they are able to maintain it."
On his three-day trip to the towns of Kitgum and Lira in the far north McAvoy insisted on getting his hands dirty.
In baking heat, he spent hours unloading heavy bags of millet and handing out essential items and passing bags of medical equipment to pregnant women.
None of the thousands in the camp knew he was a successful actor, assumed he was another volunteer - and politely thanked him for being there. For the last two decades the displaced villagers have relied on charities like the British Red Cross just to survive.
There is a fragile ceasefire between the Lord's Resistance Army and the government - but there are serious fears that it won't last.
THE LRA, who want to run Uganda under strict Biblical laws, has fought a guerrilla war in the North.
They have destablised the area by targeting remote towns and villages, committing massacres and kidnapping children and forcing them to fight with them.
They are notorious for forcing youngsters to carry out raids on their own villages, murdering their own friends and relatives. In Oteno village McAvoy met teacher Abong Hannington who had fled with his wife and three children when the LRA struck.
Five people in his village were killed and 20 children abducted. McAvoy was visibly moved.He said: "It disturbs me a lot. It makes me very sad, but what disturbs me even more is that this has been going on for 20 years and I knew nothing about it.
"Over 1.5million people have been affected - it's a ridiculous figure. F**king hell! I can't believe this is going on.
"We have meddled in Africa for hundreds of years, we have f**ked this continent up royally."
McAvoy has three films coming out in the next six months. In Becoming Jane he stars with Anne Hathaway, in Penelope with Reese Witherspoon and in Atonement with Keira Knightley. He had been wondering how he could help the Ugandan people when the Red Cross contacted him, asking if he was willing to work with the charity?
"I said 'How about in Uganda?' I definitely owe a debt to the country and I hope my being here can help."
ONTD