BANGKOK, June 20 -- Thousands of anti-government protesters marched to the Government House to storm the office of Thailand's Prime Minister Samak Sundaravej.Clad in the royal colour of yellow and carrying the portraits of Thai King Bhumibol Adulyadej, the protesters chanted anti-government slogans in the country's administrative centre.Hundreds of riot police are put on standby and major roads leading to the GovernmentHouse were closed. This is the biggest anti-government rally since the last general election four months ago.--fotoBERNAMA COPYRIGHT RESERVED