Jeff Savage, 48, who was arrested almost two weeks ago following major unrest in the Far East nation, worked as a Buckingham Palace general porter in the kitchens.
Mr Savage, from Tonbridge, Kent, was employed intermittently during a five-year period from 1993 and reportedly had the use of a grace-and-favour flat in the Royal Mews.
A Buckingham Palace spokeswoman confirmed he was a former member of staff but would not comment further.
The 48-year-old was captured on video exhorting protesters to set fire to the Central World shopping centre in central Bangkok, days before it was torched and destroyed.
Mr Savage, who has lived in Thailand for nine years, was filmed wearing a bandana and saying of Central World: "We're gonna loot everything, gold, watches, everything, and then we're gonna burn it to the ground."
Mr Savage later said from a Bangkok remand prison, where he was taken after being arrested at the end of last month: "I am being stitched up, being fitted up."
Mr Savage went on to deny any involvement in the destruction of the shopping centre.
The Thai government is reportedly preparing to charge him with violating the state of emergency decree, an offence which carries a two-year prison sentence.