Bangkok (AFP) — Thailand’s Supreme Court ordered on Tuesday the country’s most powerful and polarising politician Thaksin Shinawatra to be jailed for one year, ruling that he improperly served a 2023 prison term in hospital.

Shinawatra’s political clan has for two decades been the key foe of Thailand’s pro-military, pro-royalty elite who view their populist brand as a threat to traditional social order.

The dynasty’s momentum is flagging after a litany of legal and political setbacks, culminating in his daughter Paetongtarn Shinawatra being ousted last month from the prime minister’s office.

But Tuesday’s Supreme Court ruling deals one of the most painful blows yet to Thailand’s biggest political heavyweight, as judges ordered the 76-year-old’s transfer to Bangkok Remand Prison.

A corrections department official, speaking on condition of anonymity, told AFP on Tuesday afternoon that he had “entered the prison.”

Thaksin was elected prime minister in 2001 and again in 2005, but took himself into exile after his second term was cut short by a military coup.

After returning in August 2023 he was sentenced to eight years for corruption and abuse of power.

But he never spent a night in a cell — whisked to a private hospital room, his sentence was reduced to one year by royal pardon, before he was freed in an early release scheme for elderly prisoners.

The timing of his return and his medical transfer, which coincided with his Pheu Thai party forming a new government, had fuelled public suspicion of a backroom deal and allegations of special treatment.

“The enforcement of the defendant’s prison sentence was unlawful,” said the Supreme Court ruling read aloud to Thaksin and an audience of journalists and lawyers.