Mother-love's dark side exposed at Cannes

"Mothers," says young cult Korean director Bong Joon-ho, "can be noble figures, or savage beasts. We all know that."

"I hope my mother doesn't read this," added the fresh-looking 39-year-old director of award-winning "Memories of Murder" and "The Host" after triumphing at the Cannes festival with his latest and very different film, "Mother".

Not a newcomer to violence, Bong in his two-hour movie unravels a tense mother-son relationship which as the plot develops shows a woman ready to go to any lengths to save her child.

"I wanted to explore her feelings, the feelings of all mothers, the mothers you see in Korea, even my own mother," he told AFP. "I'm a father, I've had these feelings."

Casting veteran 70-year-old Korean star Kim Hye-ja as the single mother of a grown but mentally-challenged boy, repeatedly insulted as "a retard" by his peers, Bong recounts his arrest for the murder of a school-girl and his mother's quest to prove his innocence.

But the highly intense film also highlights the oppression of the ties between the pair.

If Anthony Perkins' mother in Alfred Hitchcock's seminal thriller "Psycho" had really been alive instead of dead in the movie "I think she would've tried to control his sex-life too," said Bong.

Set in the countryside, Bong said it took researchers five months to find the right locations for the film. "The setting is composite, it's in fact lots of places that look like one place.

"I wanted the setting to be beautiful but I didn't want anywhere that anyone in Korea could recognise so that audiences would concentrate purely on the drama of the two main characters," he said.

"After exploring Korean society in previous films, this time I wanted to concentrate on psychology."

Selected by festival organisers to run for the Un Certain Regard prize for fresh upcoming talent, the lack of apparent violence in the movie contrasts with his previous works.

"I'm interested in the visible and invisible sides of violence. This film is not hard gore, the violence is invisible but just as intense," Bong said.

Would the director like his heroine be prepared to commit a crime for his children?

"I think I could if I were in a similar situation," he said. "When you lose your reason you can become a savage."

And his upcoming plans? A sci-fi animation movie based on a French graphic novel due for completion by 2012.