FACTBOX - Who are Thailand's PAD?

(Reuters) - Two thousand Thai police took up positions around Bangkok's Government House on Wednesday, tightening the noose on protesters camping outside the prime minister's office to try to oust him from power.

Following are five facts about the People's Alliance for Democracy (PAD), the motley group of royalist businessmen, academics and a retired major-general behind the movement.

* Founded in September 2005 by media proprietor Sondhi Limthongkul, a disgruntled former business associate of then Prime Minister Thaskin Shinawatra.

Sondhi appeared in a Bangkok park to rail against Thaksin, accusing him of abusing his large parliamentary majority to further the business interests of his family and friends.

* The PAD swelled into a major anti-Thaksin street movement, especially when it hooked up with Major-General Chamlong Srimuang, an ascetic Buddhist who led a successful "people power" uprising against military rule in 1992.

Its protests were key to the political turmoil that led ultimately to the 2006 coup against Thaksin. It has been targeting the current government since May 25, saying the government is an illegitimate Thaksin proxy.

* The PADs main draw card has been defence of the monarchy and 80-year-old King Bhumibol Adulyadej, regarded as semi-divine by many Thais, in the face of what they say is a bid by the Thaksin camp to turn Thailand into a republic.

PAD protesters are routinely clad in yellow. In Thailand every day is marked by a different colour and yellow is the colour for Monday, the day on which the King was born.

Thaksin and his supporters deny any challenge to the throne.