SEOUL, South Korea: He enjoyed a bit of tennis at the local club. He indulged in curry at an Indian restaurant in the west London neighborhood where he lived. As the No. 2 North Korean diplomat in UK, he chaperoned a brother of his country’s reclusive leader to an Eric Clapton concert last year.
The diplomat, Thae Yong-ho, 55, seemed to embrace the trappings of a comfortable life in a capitalist capital thousands of miles from dreary N.Korea, never hinting at disloyalty. He had lived in London for a decade, trusted because of his family’s impeccable legacy in North Korean history.
So it was a shock on Wednesday when S.Korea announced that Mr. Thae had betrayed his hermetic homeland by becoming the most senior North Korean official to defect in nearly two decades.
How and when the diplomat had eluded his colleagues at the North Korean Embassy, who are required to monitor one another to thwart treason, was not clear. But a South Korean government spokesman, Jeong Joon-hee, said at a news conference that the diplomat had arrived recently in South Korea with his wife and family, proclaiming disillusionment with the increasingly isolated government of the North Korean leader, Kim.
Mr. Jeong did not specify how many family members had accompanied Mr. Thae or whether any remained in N.Korea, where they could be at risk of reprisal. Nor did he explain the route taken by Mr. Thae, second in rank to Ambassador Hyon Hak-bong in London.
“We see his defection as a sign that some of the core elite in the North are losing hope in the Kim Jong-un regime,” Mr. Jeong said, “and that the internal unity of the ruling class in the North is weakening.”
South Korean officials expressed similar conclusions in April when 13 people working at a restaurant run by the North Korean government in China fled to the South. Officials said that unusual group defection reflected growing dissatisfaction in the North.
But analysts have cautioned against drawing such conclusions.
Cheong Seong-chang, an expert on North Korea at the Sejong Institute in Seoul, said that isolated defections like Mr. Thae’s should not be taken as an indication of instability in the North, and that there was no sign of an organized challenge to Mr. Kim’s rule.
Others were cautious because some North Korean defectors to South Korea have not always found happiness, a message that may have found its way back to Pyongyang, the North’s capital, and elsewhere.
“I think we will continue to see senior defections but at a trickling pace,” said Jae H. Ku, director of the U.S. Korea Institute at the Johns Hopkins University’s School of Advanced International Studies in Washington. “I don’t think we are at a point where we will see massive defections by elites because these elites have not yet found ways to live comfortably in South Korea.”
Still, Mr. Thae’s defection could yield a trove of intelligence information. It came as relations between the Koreas had worsened over the North’s nuclear weapons and missile programs, tested in defiance of international sanctions.
While the North had no immediate reaction to the defection announcement, it was seen in the South and elsewhere as a major embarrassment for Mr. Kim, who has disciplined subordinates by demoting them or in some cases executing them.
The last time a North Korean diplomat of such high rank defected was in 1997, when Jeun Sun Gil, the ambassador to Egypt, sought refuge in the United States with his younger brother, a North Korean diplomat in Paris.
Inklings of a betrayal in the North Korean Embassy in London surfaced a few days ago when a South Korean mass-circulation newspaper, JoongAng Ilbo, quoted an anonymous source saying a diplomat there had defected in early August after “painstaking preparation.” By the time other embassy officials realized this, the newspaper said, the diplomat had fled.
Mr. Thae has been well known in the British news media, acting as the embassy’s main point of contact for British correspondents traveling to Pyongyang. Reuters reported that Mr. Thae spoke regularly at far-left events in London, including meetings of a British Communist Party where he would make impassioned speeches in defense of North Korea