A court in Thailand has found the wife of the country's former prime minister, Thaksin Shinawatra, guilty of tax fraud.

Potjaman Shinawatra was sentenced to three years in prison on Thursday for failing to pay $16m in tax connected to the family's telecommunications business.

She was released on bail pending an appeal - as were her brother and secretary who were also convicted in the case.

Three hundred police had been placed on duty around the courthouse in Bangkok to prevent trouble between Thaksin supporters and opponents.

The conviction comes after Thailand's supreme court accepted another lawsuit against the former prime minister, alleging that he gave illegal soft loans to Myanmar to benefit his telecoms firm.

Thaksin's lawyers have denied all charges, claiming they are attempts by his political opponents to discredit him.