<sod > Thae Yong Ho, Pyongyang's former deputy ambassador to London, defected to neighbouring South Korea last year A defector has called on North Koreans to rise up against dictator Kim Jong-Un's regime and 'set the country on fire' 'When Kim Jong Un first came to power, I was hopeful that he would make reasonable and rational decisions to save North Korea from poverty, but I soon fell into despair watching him purging officials for no proper reasons,' Thae said during his first news conference with foreign media on Wednesday.< eod>< sod >  Thae Yong Ho, Pyongyang's former deputy ambassador to London, defected to neighbouring South Korea last year A defector has called on North Koreans to rise up against dictator Kim Jong-Un's regime and 'set the country on fire' Their British friends at school made fun of them over the nature of their homeland, he said. For instance, when they grew long hair, their friends laughed and asked whether they could be arrested in North Korea because they had heard all young men were required to have short haircuts. 'These kinds of questions bombarded my sons,' Thae said. Thae, who said as a diplomat abroad he had the privilege of access to outside information, said he decided to talk frankly with them about North Korea. He concluded that his sons would have 'miserable' lives if they returned home because they had come to know the truth about the country. Ahead of their defection to South Korea, Thae said he told his sons that he was going to 'cut the chains of slavery and you are free men.' He said his sons are happy and are 'now feeling a true sense of freedom' in South Korea. Thae said his disappointment with North Korean leader Kim Jong Un was another reason he defected. He said he initially had some hopes for Kim but eventually fell into 'despair' after watching him execute officials without proper reasons and pursue development of nuclear weapons.< eod>