A Thai court has dismissed Prime Minister Srettha Thavisin for appointing to his cabinet a former lawyer who was once jailed.

The Constitutional Court ruled that Mr Srettha had violated the “rules on ethics” with “the display of defiant behaviour”.

The 67-year-old Srettha, who has been in power for less than a year, is the third PM in 16 years to be removed by the same court.

He will be replaced by an interim leader until Thailand’s parliament convenes to elect a new prime minister.

“I’m confident in my honesty … I feel sorry, but I’m not saying I disagree with the ruling,” he said at a press conference shortly after the ruling.

The verdict signals political uncertainty for a country that has seen multiple coups, the last being in 2014 when the military seized power.

Although a young, reformist party won the most votes and seats in last year’s general election, the military-appointed senate did not allow the Move Foward party to form a government.

The opposition Pheu Thai party which was the second-biggest winner agreed to form a coalition without Move Forward, and put forward Mr Sretta as their PM candidate.

His appointment ended nine years of military rule in Thailand.

On Wednesday, the court voted five to four to remove Srettha from office. The court’s ruling is final and cannot be appealed.

Earlier this May, the court had accepted a petition filed by some 40 senators asking to remove Srettha from his position for his appointment of Pichit Chuenban – who previously been sentenced to six months in jail for an attempted bribery case.