South Korea's top court has upheld a life sentence for the captain of a ferry that sank last year, killing more than 300 people, most of them teenagers on a school trip.

The Supreme Court upheld a lower court ruling which sentenced Lee Joon-seok, 70, to life imprisonment on charges that included homicide, the court said in a statement.

The court ruled that Lee committed homicide by "wilful negligence", concluding that he fled his ship without giving an evacuation order, although, as captain, he is required by law to take measures to save his passengers.

The court also upheld prison terms of 18 months to 12 years for 14 other crew members who faced similar charges of negligence and passenger abandonment, but were not found guilty of homicide because they were subject to Lee's orders.

A total of 304 people died when the ferry Sewol sank off South Korea's south-west coast in April 2014 in one of the country's deadliest maritime disasters. Most of the victims were from a single high school.

Lee and his crew members have been the targets of fierce public anger because they were among the first people rescued from the ship when it began badly listing.

Lee said he issued an evacuation order, but many survivors said they were repeatedly ordered over a loudspeaker to stay on the sinking ferry and did not remember any evacuation orders before they escaped.

The court ruled there was stronger evidence showing that Lee did not issue an evacuation order, and that he abandoned his duties as captain.

Lee's failure to take measures to save his passengers made it impossible for many to escape, the court said, meaning it was as if he had drowned them himself.

Divers recovered 295 bodies from the ship's wreckage and nearby seas before the government stopped underwater searches in November last year. Nine victims remain missing.

The tragedy touched off an outpouring of national grief and soul-searching about public safety. The relatives of the victims, angry that higher-level officials have not been held accountable, have been calling for a stronger investigation into the government's responsibility for the disaster, which was blamed in part on official incompetence and corruption.

South Korea is paying 74 million US dollars (£48.8 million) to a consortium led by China's state-run Shanghai Salvage Co to handle the difficult job of raising the 6,800-ton Sewol. The government expects the ship to be salvaged by next July.

Relatives of the victims hope that raising the ship will help find the nine missing bodies and reveal what caused the ferry to sink.