Donald's secret diary is finally cracked

Click video. Now a remarkable story about a truly remarkable man. Donald Hill was an officer in the RAF. He was captured by the Japanese and became a prisoner of war and spent four years in a camp in Hong Kong.

Donald kept a diary that he wrote in secret mathematical code. Years after his death the code was finally cracked, and his family found out for the first time what he went through during the war. Heather Edwards reports.