South Korea’s impeached president has been released from detention after a court in Seoul overturned his arrest on technical grounds.

Yoon Suk Yeol walked free on Saturday to cheers from his supporters – but still faces trial on insurrection charges after his failed attempt to impose martial law in December.

He was arrested in January in a dawn raid at the presidential palace after a tense fortnight where he had resisted being taken in and there were clashes between his security detail and police.

But he walked free on Saturday after 52 days in custody. “I bow my head in gratitude to the people of this nation,” he said in a statement distributed by his lawyers following his release.

After waving to supporters outside the centre, he was driven in an official convoy back to the presidential compound in Seoul, where he was greeted by more supporters.

More than 50,000 protesters staged rallies in his support in the capital on Saturday, while there was also a slightly smaller counter-protest, Yonhap reported.

Mr Yoon’s lawyers secured his release after arguing it was illegal to hold him in custody. The courts agreed, based on a number of legal technicalities, although the prosecutors described the ruling as “unjust”.

He is due to stand trial later this year for the attempt to put the democratic country under martial law. It only lasted six hours – but polarised the nation.

If convicted he could face life in prison or even the death penalty.

Although currently suspended from office, Mr Yoon is still South Korea’s president in name.

He also faces a separate Constitutional Court ruling which will decide on whether to uphold his impeachment and formally strip him from office. The judges’ decision is expected in the coming days.

Despite the court cases, Mr Yoon’s supporters have rallied around him – and authorities are bracing themselves for unrest.