Khattiya requested bail based on his position in the Royal Thai Army and was released on Bt50,000 bail, pending his bid to try to overturn the ruling within 30 days.

The court found Khattiya guilty of defaming Seripisut, then an inspector-general, for comments about his crackdown on gambling dens.

The court did not suspend the jail term for Khattiya, even though it was his first criminal offence. It said that as a senior officer making accusations against others, the public was likely to believe him.

The court also ordered Khattiya to pay for publication of the ruling in Naew Na, the Daily News and Thai Post newspapers for seven days.

In the defamation case, Seripisut claimed that Khattiya in interviews with Naew Na on February 20, said Seripisut had raided a Bangkok gambling den to bolster his reputation, improve his chances of being promoted and attempt to have his brother-in-law, Lt-Colonel Thavornsak Thepchat-ree, made Metropolitan Police commissioner. The remarks were published on February 21 last year.

As well as Thai Post, the Daily News, Manager website, www.sae-dang.com and Modern 9 TV also published the remarks, which convinced the court that if Khattiya was misquoted, he could have argued with them.

The court also regarded Khattiya's comment that "a certain individual was involved in a gambling-den loft in Pin Klao area" as part of the remarks directed at Seripisut. This was based on his previous remarks to the media that he believed Seripisut cracked down on the gambling den downtown for personal gains - and to get more people going to the Pin Klao den.

It said the defendant's actions made the public believe Seripisut had violated laws himself, when he was just doing his job.

As a result, the court found Khattiya guilty of defaming a working officer via advertising, according to Criminal Code articles 136 and 328.

Khattiya said he would fight the ruling within 30 days.

He said an order by then deputy prime minister Chidchai Vanasadiya to appoint Seripisut as the chairman of a panel to crack down on influential figures was cancelled on January 16, 2006 - three weeks before the gambling den raid. That made Seripisut's action unauthorised, he claimed.

He said he would also protest that his lawyer had pulled out of the case - with no clear reason - leaving him unable to find one to represent him in the primary court.

The Criminal Court previously issued an arrest warrant for Khattiya for failing to appear at a session last month when the verdict was read.

Nearly 30 defamation cases filed by Seripisut against Khattiya are currently being considered by the Ratchada Criminal Court and the Southern Bangkok Criminal Court.