The most senior diplomat to have defected from North Korea will run for parliament in South Korea to “give hope” to tens of thousands of others who have fled the regime, media reports said on Tuesday.

Thae Yong-ho was deputy ambassador at the North Korean embassy in London when he defected with his wife and two sons in August 2016, and has since become one of the regime’s most vocal critics.

Thae, who was denounced as a traitor by North Korea, will run in the national assembly elections on 15 April for Liberty Korea, the country’s conservative main opposition party, officials said.

“Thae is someone who risked his life for freedom,” Kim Hyong-o, a party official in charge of candidacies, told reporters. “As a person who understands the sorrow of the 10 million separated families, and as one of 25 million North Koreans, he could present a vision for peace.

“His courage and decision will give hope to North Korean refugees and other South and North Korean people who want genuine unification.”

If elected, Thae, 57, would become the second North Korean defector to win a seat in the national assembly. The first was Cho Myung-chul, who fled to the South in 1994 and represented a predecessor to Liberty Korea from 2012-16. Party officials said Thae was likely to campaign for a seat in a Seoul constituency.

He sparked jubilation in South Korea, and anger in his former homeland, when he became one of very few senior North Korean officials to defect.

The regime in Pyongyang denounced him as “human scum” and accused him of misusing government funds and other crimes.

More than 30,000 North Koreans have defected to the South since the end of the 1950-53 Korean war, but most are people fleeing poverty in rural areas near the Chinese border.

The most high-ranking North Korean to have defected is Hwang Jang-yop, once a senior official with ruling Workers’ party who once tutored Kim Jong-il, the country’s former leader and father of its current leader Kim Jong-un. Hwang died in 2010.

Thae said soon after he arrived in Seoul that he couldn’t bear the thought of his children leading “miserable” lives in the North, adding that he had lost confidence in Kim Jong-un after the leader began executing officials and developing nuclear weapons.