North Korea’s deputy ambassador in London has defected to South Korea with his family, suggesting the growing instability of the North’s regime under a ruthless and reckless young leader.

The Unification Ministry on Wednesday confirmed domestic and British media reports that Thae Yong-ho, a minister at the North’s embassy in London, has defected.

The ministry said Thae and his family arrived in Seoul, denying media reports that they were seeking asylum in a third country.

Thae is one of the highest-ranking North Korean diplomats to have defected to the South. His defection is also the latest in a recent series of high-profile escapes by the North’s elite.

Thae’s flight deals a serious blow to leaders in Pyongyang, as he is one of the North’s best and most trusted diplomats. In the North, diplomats are carefully groomed and Thae is no exception.

Hailing from a privileged family, Thae has held a series of coveted diplomatic posts. His 10-year tenure at the London embassy illustrates that he belongs to the North’s core group of diplomats, as London is one of the most important diplomatic centers for the isolated Pyongyang regime.

At the London embassy, Thae was in charge of promoting North Korea, a job that must have been increasingly difficult after the United Nations imposed its toughest sanctions on Pyongyang for its illegal nuclear test and missile launch earlier this year.

The Unification Ministry cited as motives for Thae’s defection his growing discontent with the regime of Kim Jong-un, a yearning for the free democratic system in the South, and concerns about the future of his children. He must have thought that there was no hope under Kim.

This sense of hopelessness might be shared by a growing number of public officials and affluent people in the North, explaining the recent increase in the number of North Koreans escaping from the country.

The increase in North Korean defectors indicates that harsh international sanctions against the regime have begun to have an impact.

Under strong external pressure, the regime’s internal solidarity is weakening. Recent defections suggest that discontent is growing in the North’s military and officialdom, the core groups that buttress the shaky regime.

The Seoul government needs to separate the North’s elite and ordinary people from its leadership and send different messages to them.

During a speech to mark the Aug. 15 Liberation Day, President Park Geun-hye tried to do that. She urged the North’s elite and ordinary people to join Seoul’s efforts to lay the groundwork for national reunification.

She sought to inspire hope among them by saying that if the two Koreas reunite, all people will be treated equally without discrimination and disadvantages, and be able to pursue happiness while realizing their full potential.

The Seoul government needs to further shake the regime’s foundation by sending messages of hope and courage to the North’s core groups and ordinary people.