Suvit Saethang, a 34-year-old Thai office worker, and his extended family joined tens of thousands of others in Bangkok's Lumpini park on Friday evening to listen to an angry man, whose crusade against prime minister Thaksin Shinawatra is sending political tremors through the capital.

Media baron Sondhi Limthongkul, formerly a staunch Thaksin supporter, is an unlikely rallying point for simmering public discontent with a premier who won a landslide re-election less than a year ago. But since September, Mr Sondhi's weekly public tirades - lambasting the premier for abuse of power, conflicts of interest and cronyism - have drawn vast crowds, eager to register their opposition to Mr Thaksin and his authoritarian style.