North Korea has released video footage and a photograph which appears to show the heir apparent Kim Jong-un.

It is the world's first up-to-date glimpse of the young man who appears set to succeed his father, Kim Jong-il, in a gradual transfer of power.

Footage aired on state-run TV showed him at this week's rare meeting of the ruling Workers' Party, where he was promoted to top political and military positions.

John Sudworth reports.