Song Byeok was once the official state propaganda artist of North Korea. He created paintings and posters celebrating the country's revered leaders Kim Jong-Il and Kim Il-Sung.

His faith in the regime was betrayed in the 1990s when famine struck North Korea. Millions of people, including Song's father, mother, and sister, died.

In search of food, Song tried to cross the border into China. His father drowned in the swollen flood waters and Song was arrested and sent to a prison camp.

After his release he managed to escape in 2002 to South Korea. There he turned his artistic skills against the regime in his homeland.

An exhibition of his latest work - which also criticises other oppressive regimes around the world - is currently on display at the Woolly Mammoth Theatre in Washington DC.

Produced by the BBC's Bill McKenna. With thanks to Gregory Pence, Sojeong Kim and Sandbrush Inc.