A propaganda campaign for North Korean leader Kim Jong-il's heir apparent Kim Jong-un has been in full swing nationwide since May last year, a witness said Thursday.

That month the party distributed schools materials hailing "Captain Kim," as Jung-un apparently likes to be known, as leader of a "150-day struggle."

The testimony comes from a 25-year-old North Korean middle school teacher who defected to the South last December. She made the remarks at a press conference at Hanawon, the institute supporting the resettlement of North Korean defectors, to mark its 11th anniversary. She said that was when "Footsteps," a song praising Kim junior, was first sung.

The 150-day struggle from April to September last year was a widely unpopular attempt to revive the regime's collapsing economy that pressed huge numbers of people into farm work. That the Kim Jong-un personality cult was underway at the time is confirmed in a film released in the North in February that records Kim Jong-il's so-called on-the-spot guidance trips and the 150-day struggle. It has a scene where a man looking like an instructor teaches a song to farmers in a village.

A screen grab from a North Korean film released early this year shows a man teaching villagers the song "Footsteps" hailing and praising Kim Jong-un.

According to the former teacher, the 50 pages of A5 paper record Kim junior's supposed achievements. In addition to his feats in the 150-day struggle, it claimed that he designed extravagant fireworks displays for Kim Jong-il's birthday, Kim Il-sung's birthday and Labor Day last year, and that he accompanies Kim senior in all his guidance tours and inspects the security at each location. "A sentence even claims that rain stopped falling when Jong-un visited somewhere," the former teacher said. 

North Korean teachers were already given instructions in March last year, before the propaganda campaign started in earnest. "The deputy principal then told senior teachers that 'the young captain in his 20s' will soon become the heir apparent but not to tell the students yet," she said.