With the health of North Korea’s Kim Jong-un subject to furious speculation and a flurry of media reports, questions are inevitably being raised over who would take over control of the hermit kingdom if his reign were to be cut short.

The 36-year-old has worked tirelessly in the nine years since his father Kim Jong-il’s death to concentrate power in his own grasp, purging would-be rivals and even close family members deemed a threat to his dominion.

Chinese and South Korean intelligence services have poured cold water on suggestions, most prominently from CNN, that Kim’s life is in grave and immediate danger following heart surgery.

But they have also not denied outright that the leader has had some form of health scare, and Kim’s absence at recent events marking the 15 April anniversary of his grandfather Kim Il-sung, the founder of the nation, was considered highly unusual.

Given the leadership of North Korea has passed down through male hereditary heirs since its founding as a country – and Kim Jong-un is believed to have no adult sons – here’s who is next in line if he were to ever be incapacitated.

His sister

The only other member of the Kim family with an active role in the ruling Workers’ Party of Korea, 31-year-old Kim Yo-jong is Kim Jong-un’s younger sister and de facto chief of staff.

She has been increasingly trusted with public tasks, accompanying him at recent key summits and last month making her first official public statement, as she was reinstated to the ruling party’s most powerful politburo committee.

At the same time, it is clear from state media reports that Kim Yo-jong knows her place – behind her brother, rather than at his side. During a train stop in China early last year, she was given the job of extinguishing her brother’s cigarette.

Some analysts said that she has the only real characteristic that matters in the North Korean system – being of the “Paektu blood line”, a direct descendent of the Kim dynasty.

But North Korea is also a rigid patriarchy, and her gender would most likely rule her out as anything more than a caretaker leader in the event of her brother’s demise.

Simply put, said Leif-Eric Easley, associate professor of international studies at Ewha Womans University in Seoul: “The North Korean system could not continue in its current ideological and institutional form without an adult male descendant of Kim Il-sung.”

His brother

Kim Jong-un has a surviving older brother, who was passed over for consideration when Kim Jong-il decided which of his children to groom as the country’s next leader.

Kim Jong-chol is said to have been more keen on music and playing guitar than politics, and is living a quiet life away from the spotlight in North Korea, according to Thae Yong-ho, North Korea’s former deputy ambassador in London who defected to the South.

He was last spotted in 2011 enjoying an Eric Clapton concert in Singapore, according to South Korean broadcaster KBS. Like his brother, he also studied abroad in Switzerland.

According to Kenji Fujimoto, the Japanese man who claims to have been the personal sushi chef for Kim Jong-il, the late North Korean leader decided Kim Jong-chol was too “girlish” to lead the country. It would seem to be a long shot for him to return to the fold of public life.

His son

The private life of North Korea’s first family is notoriously shrouded in mystery, but we do know that he has been married to former singer and cheerleader Ri Sol-ju since 2009.

South Korea’s intelligence services believe the couple have had three children – including a son born in 2010, a daughter born around 2013 and third child in 2017.

Bizarrely, perhaps the best insight into the Kim family came from the 2013 visit of US basketball star Dennis Rodman, who described Kim Jong-un as a “good dad” to his then-young daughter Ju Ae.

Kim Jong-un: Power in pictures Show all 20 1 /20 Kim Jong-un: Power in pictures Kim Jong-un: Power in pictures Kim Jong-un rides a horse during snowfall in Mount Paektu in this image released by North Korea's Korean Central News Agency on 16 October 2019 Reuters Kim Jong-un: Power in pictures Kim Jong-un visits the newly built Pyongyang Orphans' Primary School on 2 February 2017 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un inspects a women's company under Unit 5492 of the Korean People's Army in November 2019 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un inspects the test-fire of intercontinental ballistic missile Hwasong-14 at an undisclosed location in July 2017 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un celebrates the successful test-fire of the intercontinental ballistic missile Hwasong-14 at an undisclosed location in July 2017 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un inspects a potato at the Samjiyon Potato Factory in North Korea in October 2018 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un rides a horse through a forest in this image released by North Korea's Korean Central News Agency on 16 October 2019 EPA Kim Jong-un: Power in pictures Kim Jong-un inspects a block of frozen fish at a processing facility in North Korea in November 2018 Reuters Kim Jong-un: Power in pictures Kim Jong-un celebrates the succeful launch of a strategic submarine-launched ballistic missile in August 2016 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un shakes hands with Donald Trump as they meet for the first time at the Capella Hotel on Sentosa island in Singapore in June 2018 Reuters Kim Jong-un: Power in pictures Kim Jong-un and Donald Trump share a glance as they meet in the Demilitarised Zone in Panmunjon, Korea in June 2019 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un inspects mushrooms at Pyongyang Mushroom Farm AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un inspects a super-large multiple rocket launcher ahead of a test in September 2019 Reuters Kim Jong-un: Power in pictures Kim Jong-un inspects an apple farm in South Hwanghae Province in September 2017 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un inspects an apple farm in South Hwanghae Province in September 2017 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un inspects dental wares at a newly built factory in June 2017 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un visits Farm No 1116 in September 2017 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un visits a motor factory in November 2017 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un rides a horse during snowfall in Mount Paektu in this image released by North Korea's Korean Central News Agency on 16 October 2019 AFP/Getty Kim Jong-un: Power in pictures Kim Jong-un inspects the Command of the Strategic Force of the Korean People's Army at an undisclosed location in August 2017 AFP/Getty

The ages of Kim’s children mean that a form of regency would be required until his eldest son was old enough to take over.

Nonetheless, US officials believe that keeping control of the country within the family is still the most likely outcome. Speaking on Fox News on Tuesday, Donald Trump’s national security adviser Robert O’Brien said of any succession: “The basic assumption would be maybe it would be someone in the family.”

The top officials

North Korea’s most senior officials have stayed in their jobs through unflinching loyalty to the Kim family, sometimes over multiple generations.

In the event that new leadership is required, it is possible that several high-ranking Workers’ Party elders could team up to see the country through any transition.

After decades of service including as Kim Jong-un’s first military chief, Choe Ryong-hae rose to be the North’s nominal head of state last year becoming the president of the Presidium of the Supreme People’s Assembly.

He and Pak Pong-ju, a fellow politburo member and former state premier who oversaw the North’s push to introduce more elements of a free market to revive its economy, would be the likely figureheads of any collective leadership.

In such a scenario, the former top nuclear envoy Kim Yong-chol and foreign minister Ri Son-gwon could be tasked with handling diplomatic issues including stalled denuclearisation talks with South Korea and Washington, as they played key roles in previous summits with Trump.

Katy Oh, a Washington-based author of three books on North Korea, told The Independent that while they could help in a transition, “no male adults inside the elite structure will get the top job [itself]”.