The court described the random attack by Cho Seon in July last year as “extremely brutal” as it handed down its sentence, according to Yonhap.

Eyewitnesses at the time described scenes of horror as Seon pulled out a knife outside a subway station and stabbed a man in the back multiple times before running off to attack more people.

Cho caused “public uproar with his extremely brutal and vicious manner of crime, terrorising the public”, the Seoul Central Court said in its verdict, Yonhap reported.

The 34-year-old’s attack also resulted in “copycat crimes nationwide”, said the court, pointing to similar random attacks that followed the original incident.

“It is only fair to deprive the defendant of civic rights and freedom… and isolate him from society indefinitely to maintain social safety,” the court said.

Prosecutors had earlier sought the death penalty for the attacker.

Just two weeks after the July attack, a second mass stabbing took place when a man drove a car into a pedestrian walkway before attacking people at a department store in Seoul, killing two.

The two incidents prompted President Yoon Suk-yeol, a former top prosecutor, to call for mobilising all possible forces, with police also declaring that they would not hesitate to use firearms.

South Korea is widely considered an extremely safe country, with a murder rate of just 1.3 per 100,000 people, according to recent government data.

But in addition to the spate of random stabbing attacks, two politicians have been attacked in public, including opposition leader Lee Jae-myung, who was stabbed in the neck earlier this month.

A ruling party lawmaker was struck on the back of her head with a rock by a teenage suspect last week.