South Korean prosecutors late on January 26 formally indicted the already impeached President Yoon Suk Yeol, describing him as the "ringleader of an insurrection" following his failed declaration of martial law. The suspended leader remains in custody at the Seoul Detention Centre and is undergoing questioning.

Yoon plunged the nation into political chaos on December 3 when he sought to impose martial law, suspending civilian rule in a controversial move that lasted just six hours. The declaration was swiftly overturned as lawmakers defied armed soldiers stationed in parliament and voted it down.

In the weeks that followed millions of Koreans took to the streets across the country, protesting the move by Yoon. Efforts to have the president impeached came and went, with one late night vote falling short after an act of political theatre that saw the majority of South Korean politicians leave the chamber.

A second attempt two weeks later eventually passed the required tally but then Yoon surrounded himself by loyal guards and refused to come out of his presidential residences until a raid by over 1000 police and other officials breached the walls of his compound, ending the stand-off. He was subsequently carted off to the capital’s detention centre.

In suffering this ignominy, Yoon became the first sitting South Korean president to be arrested.

Prosecutors stated on January 26, "Yoon Suk Yeol has been indicted with detention on charges of being the ringleader of an insurrection." His detention ensures he will remain behind bars until his trial. It is understood Korean law now states that this trial must be held within the next six months.

If convicted, Yoon would become one of many South Korean presidents to be handed a prison sentence; a relatively common occurrence on the southern half of the peninsula along with military overthrow, exile and assassination with just three of the country’s 13 presidents since the late 1940s having retired scandal-free.

The indictment had been widely anticipated, especially after courts twice refused prosecutors’ requests to extend Yoon’s arrest warrant while investigations continued. Prosecutors said they reached their decision following a "comprehensive review of evidence" according to reports by AFP, and justified Yoon's continued detention due to a "risk of evidence destruction."

They emphasised that the charge of leading an insurrection is not protected by presidential immunity.

The indictment has been welcomed by the opposition, with lawmakers calling for broader accountability. Wider public opinion across South Korea also appears to be supporting the indictment according to local media. "Those who orchestrated this illegal insurrection, as well as those who incited it through misinformation, must be held to account," opposition MP Han Min-soo was quoted as saying.