The Appeal Court on Tuesday sentenced ex-deputy prime minister Plodprasop Suraswadi to two years in prison for his role in the demotion of a senior official at the Natural Resources and Environment Ministry in 2003.
In March last year, the Central Corruption Court found him guilty of malfeasance and handed down a one-year jail term suspended for two years.
In its ruling on Tuesday, the Appeal Court found him guilty on two counts under Section 157 and Section 84 of the Criminal Code and gave a one-year jail term for each of them.
The court said it decided against suspending the jail terms because Mr Plodprasop's actions could have caused serious damage to the national administration. The lawsuit was lodged by Vitoon Chalayonnawin, a former deputy chief of the Department of Marine and Coastal Resources.
According to the lawsuit, Mr Plodprasop, while serving as the ministry's permanent secretary, cancelled an order promoting Mr Vitoon to become director of a forestry office and also ensured he was transferred to a less influential post.
Mr Vitoon cited personal conflicts as the motive behind Mr Plodprasop's action.
The court found Mr Plodprasop influenced Damrong Pidech, the then chief of the Royal Forest Department, to have Mr Vitoon demoted.
Mr Plodprasop was later released on bail.