Thailand’s top court has ruled that former prime minister Thaksin Shinawatra must serve one year in jail, in yet another blow to the influential political dynasty.

It ruled that he had unlawfully served part of a previous prison sentence in a hospital, and therefore must serve it in jail.

The high-profile case is linked to a previous corruption conviction.

Thaksin and his family have dominated Thai politics since he was first elected PM in 2001. Both his sister and daughter were elected as Thailand’s leaders.

His daughter, Paetongtarn, was removed from office last month after the constitutional court ruled she had violated ethical standards, in a case linked to a leaked phone call with Cambodia’s Hun Sen.

Paetongtarn, who accompanied her 76-year-old father to court on Tuesday, told reporters after the ruling that she was “worried” for her father but that he and their family were in “good spirits”.

She also vowed to take the family’s Pheu Thai party forward in their work as an opposition party.