Wide-eyed and fresh-faced Scottish doctor, Nicholas Garrigan, swaps the stability of his homeland for thrills and adventure in Uganda, a country of poverty and desperation, in the middle of political transition.

He arrives with charitable intentions and begins work in a local hospital completely unaware of the military coup that has just taken place.

Trying to win the affections of his co-worker he takes her to the welcome rally for new President Idi Amin (Whitaker).

After the celebrations, Garrigan is stopped by Amin's soldiers and called back to treat the President who has sustained an injury in an accident in which his car has struck a cow.

While the cow lies noisily dying, Garrigan straps the president's wrist but cannot concentrate while the animal groans. Without thinking, he grabs the Presidents gun and puts the cow out of its misery.

Amin is impressed by his actions and offers him a job as a personal physician, a position which we never once believe Garrigan is able to refuse.

After an almost awkward start, Kevin Macdonald, who is best known for his feature documentaries, takes us boldly into the body of the story.

Garrigan quickly impresses Amin and is embraced into the upper echelon of his staff, providing advice and personal consultation on political issues he knows nothing about.

Only ever so slowly does he become aware of Amin's brutal regime and as this is told entirely from Garrigan's perspective, we only fully become aware of the full scale of his atrocities as he does.

The result is a film that bubbles with a sense of horror below its surface, constantly threatening to explode.

Whitaker is truly excellent as Amin, balancing perfectly the charming and likeable character that Garrigan falls for and the monster he is finally revealed to be. As is James McAvoy who convinces as the naïve doctor who falls into his fold.

Very little of the reasons behind Amin's political decisions are revealed but aren't necessary, we see him as Garrigan sees him which only increases the impact of the story.

A change in form for Macdonald who has previously concentrated his efforts on fact based stories but with this approach he is likely to succeed just as well with fiction.

Gus Crotty