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.

* There are major question marks over the PAD's motives and backers. Its contempt for the results of three elections comfortably won by Thaksin or his allies has led to suggestions it represents neither the people nor democracy.

PAD says 70 percent of MPs should be appointed rather than elected.

The alliance says it is funded by public donations. Analysts suspect it is also bankrolled by anti-Thaksin business interests, parts of the army or even factions within the palace.

* It has become something of a social phenomenon, stretching way beyond the rock-concert-like stage where they hold their daily rallies on a major Bangkok intersection.

The PAD has a radio station, satellite TV channel, several sympathetic newspaper titles and a slick, popular website.

It has also shown an uncanny ability to keep itself in the public eye and drive the domestic political agenda, jumping on issues such as a dispute with Cambodia over a 900-year-old Hindu temple to whip up anger against the government.

(Writing by Ed Cropley; Editing by Alan Raybould and Valerie Lee)