The North Korean elite are outwardly expressing their discontent toward young leader Kim Jong Un and his government as more outside information trickles into the isolated country, North Korea's former deputy ambassador to London said on Wednesday.

Thae Yong Ho defected to South Korea in August last year and since December 2016 has been speaking to media and appearing on variety television shows to discuss his defection to Seoul and his life as a North Korean envoy.

"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.