Thailand's top court ruled on Tuesday that ex-Prime Minister Thaksin Shinawatra did not serve his 2023 jail term properly, ordering him to serve one year in prison.

"Sending him to hospital was not legal, the defendant knows his sickness was not an urgent matter, and staying in hospital cannot count as a prison term," said the ruling read out by a judge.

In its ruling, the court has issued a warrant to take Thaksin to Bangkok Remand Prison to begin serving a one-year term.

The court was probing whether officials had mishandled his return to Thailand in 2023 and served time for a corruption conviction.

Thaksin had been in exile for 15 years and was accused of abuse of power upon his return to Thailand in 2023. The 76-year-old tycoon's eight-year jail term was then commuted to one year by King Maha Vajiralongkorn, and Thaksin was released on parole after spending six months at the hospital.

He spent the majority of the prison term in a healthcare facility and did not spend a night in a cell, which triggered public outrage and allegations of special treatment.

The court also said that the billionaire intentionally prolonged his stay at the hospital.

Thaksin in 'good spirits'

Following the court's verdict, Thaksin's daughter and protégée Paetongtarn Shinawatra, also a former prime minister, said that he remained "in good spirits" despite the sentence.

"My father remains a spiritual leader, whether through his past political role, his contributions to the country, or his sincere intention to be part of improving the lives of the people," she told the media outside of the court.

Ahead of the ruling, some of Thaksin's supporters had gathered outside the Supreme Court amid tight security.

Thaksin had arrived in court on Tuesday, a day after he returned to Bangkok from his surprise trip to Dubai ahead of the court ruling.

Thaksin's political dynasty in trouble

The Shinawatras' populist appeal has dominated Thai politics for the past two decades.

However, recent years have seen their popularity wane, with the emergence of the progressive Move Forward Party, which was disbanded in 2023 despite winning the most seats in an election that year.

Last month, the tycoon's  daughter Paetongtarn Shinawatra was sacked from the prime minister post by the country's Constitutional Court over a leaked phone call with Cambodian Senate President Hun Sen over a border dispute that escalated into deadly clashes.

Edited by: Rana Taha