When Donald Trump meets North Korean leader Kim Jong-un on Tuesday for perhaps the most significant nuclear talks since the Cold War, the American president will have his link to the US nuclear arsenal nearby at all times.

As the leader of a newly minted nuclear state, much less is known about how Mr Kim maintains control of his nuclear arsenal while he travels.

The North Korean leader began the year by declaring to the world that “a nuclear button is always on the desk of my office”, which was widely interpreted as an allusion to his personal control over his country's nuclear arsenal.

Mr Trump fired back a tweet, saying: “I too have a Nuclear Button, but it is a much bigger & more powerful one than his, and my Button works!”

When the two meet in Singapore for high-stakes nuclear negotiations, Mr Trump will be accompanied, as always, by a staffer carrying his “button” in the form of the “nuclear football” containing equipment used to authorise a strike.

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North Korea is one of the most insular states in the world and command and control of its nuclear facilities is kept within a tight, impenetrable circle.

Additionally, Mr Kim – who came to power in 2011 – has only just begun making trips outside North Korea. He has been to Beijing twice and has briefly crossed the frontier at the Demilitarised Zone with South Korea to meet its president. Singapore will be the furthest he is known to have travelled since taking over.

But analysts who closely watch North Korea believe it is unlikely Mr Kim would have come to Singapore without being confident of the arsenal’s security – and the ability to order its use.

Singapore Summit: historic first meeting between Trump and Kim Jong-un Show all 20 1 /20 Singapore Summit: historic first meeting between Trump and Kim Jong-un Singapore Summit: historic first meeting between Trump and Kim Jong-un Mr Trump and Mr Kim leave following their historic meeting AFP/Getty Singapore Summit: historic first meeting between Trump and Kim Jong-un Mr Trump and Mr Kim sign a document committing to peace between their nations, amongst other things EPA Singapore Summit: historic first meeting between Trump and Kim Jong-un Mr Trump holds up a document that both he and Mr Kim have signed AFP/Getty Singapore Summit: historic first meeting between Trump and Kim Jong-un The two leaders reach out to shake hands for the first time AP Singapore Summit: historic first meeting between Trump and Kim Jong-un Mr Trump and Mr Kim shake hands as they meet for the first time Reuters Singapore Summit: historic first meeting between Trump and Kim Jong-un Mr Trump and Mr Kim walk off stage, following their historic meeting Reuters Singapore Summit: historic first meeting between Trump and Kim Jong-un Mr Trump and Mr Kim take a stroll after their meeting on June 12 Reuters Singapore Summit: historic first meeting between Trump and Kim Jong-un Mr Trump and Mr Kim interrupt their stroll to talk to the media AP Singapore Summit: historic first meeting between Trump and Kim Jong-un Mr Kim and Mr Trump look out over a balcony at the Capella hotel, where they held their meeting on June 12 Reuters Singapore Summit: historic first meeting between Trump and Kim Jong-un Mr Trump takes questions at the press conference following his meeting with with Mr Kim AP Singapore Summit: historic first meeting between Trump and Kim Jong-un Mr Trump appreciates the crowd in the press conference following his meeting with Mr Kim Getty Singapore Summit: historic first meeting between Trump and Kim Jong-un Mr Trump travels to the Istana ahead of the summit with Kim Jong Un on June 12 Reuters Singapore Summit: historic first meeting between Trump and Kim Jong-un Kim Jong Un travels to the Istana ahead of the summit with President Trump on June 12 Reuters Singapore Summit: historic first meeting between Trump and Kim Jong-un Mr Kim poses for a photo with Singapore's Finance Minister Vivian Balkrishnan and Education Minister Ong Ye Kung ahead of the summit with Mr Trump Twitter/Reuters Singapore Summit: historic first meeting between Trump and Kim Jong-un Mr Trump shakes hands with Singapore Prime Minister Lee Hsien Loong, meeting on Monday June 11 in the Istana, Singapore's presidential palace AP Singapore Summit: historic first meeting between Trump and Kim Jong-un At a working lunch on Monday, Singapore's Prime Minister surprised Mr Trump with a birthday cake, in early celebration of his 72nd birthday later in the week EPA Singapore Summit: historic first meeting between Trump and Kim Jong-un US Secretary of State Mike Pompeo answers questions about the summit at a press briefing in Singapore on Monday, June 11 Getty Singapore Summit: historic first meeting between Trump and Kim Jong-un US President Donald Trump arrives at the Paya Lebar Air Base in Singapore on June 10, two days prior to his summit with North Korean leader Kim Jong Un Reuters Singapore Summit: historic first meeting between Trump and Kim Jong-un Mr Trump and Mr Kim met on Tuesday June 12 in the Capella hotel on the island resort of Sentosa, just off the south coast of Singapore AFP/Getty Singapore Summit: historic first meeting between Trump and Kim Jong-un Mr Trump boards Air Force One following the summit AFP/Getty

“We don’t know how developed North Korea’s secure communications capabilities are, so whether Kim Jong-un will be within easy reach of his National Command Authority during his stay in Singapore is an open question,” said Andrew O’Neil, a North Korea nuclear policy expert at Griffith University in Queensland, Australia.

“That said, given that most assume... North Korea’s nuclear command, control, communications and intelligence is configured to promote a high degree of centralisation in Kim’s decision-making, it beggars belief that Kim would not be within secure reach to authorise a possible launch if required,” Mr O’Neil added.

Mr Kim likely delegated authority to watch over the arsenal to one of a number of trusted North Korean officials who stayed in Pyongyang, including Choe Ryong Hae, one of several senior leaders who saw Kim off at the airport as he departed for Singapore, said Michael Madden, a leadership expert with the 38 North website, which monitors North Korea.

“Kim can authorise or approve a missile strike while he is away,” Madden said. “There’s a protocol for launches.”

Trusted officials would maintain control of fixed telecommunications hotlines in the country, and there is likely a code system to activate the systems involved in launching North Korea’s ballistic missiles.

“There are only certain designated facilities where these communications can be activated,” Mr Madden said

Many questions remain unanswered, however, including whether the North Koreans have robust enough communication systems to make sure no one panics and launches an attack, said Vipin Narang, an associate professor at the Massachusetts Institute of Technology’s Security Studies Program.

“Its command and control structure while Kim is travelling is unlikely to be robust enough for him to be able to reliably issue or stop launch sequences,” he said.

He said that was because North Korea was likely to have configured its nuclear forces to permit rapid authorisation to launch in order to offset the risk of a first strike from the United States.