A top defector from North Korea told a committee of US lawmakers in Congress that Kim Jong-un's grandfather did not even know that the future dictator existed during his early years. Former ambassador to the UK Thae Yong-ho described Kim as a "hidden boy" when he was a child.

Thae was talking about the need for the US to increase its information activities in North Korea to help show people trapped in the dictatorship about the lies of the regime and truth about the outside world.

"Much more needs to be done to increase the flows of information into North Korea," Thae told the House Foreign Affairs Committee on 1 November, arguing that the demand for South Korean culture was only rising among the people in North Korea – prompting the regime to start selectively releasing foreign films.

Thae commented that an Arab Spring-style revolution was becoming more plausible in the hermit kingdom. It is "increasingly possible to think about civilian uprising in North Korea," Thae said.

Tensions between North Korea and the US have continued to heat up as the country continues efforts to develop a nuclear intercontinental ballistic missile that could reach the continental United States.

The former deputy ambassador also had strong words for China, arguing that the country needs to better deal with North Korean defectors, saying that currently there are thousands of North Koreans living paperless in China and suffering both physical and sexual exploitation.

Thae defected to South Korea in the summer of 2016, provoking a frenzied response. The state-run news agency branded him as "human scum" and accused him of sex crimes. During the hearing, Thae said that it was thinking about his sons that led to his defection.

Having lived with them in London, Thae said he did not know how his sons would be able to reacclimatise if he were to take them back to North Korea. "I could not take back the happy smiles of my sons by bringing them back to North Korea," Thae said.