The western of the Royal Thai Army has been introduced by King Rama V who extensively travel to Europe. He chosen to emulate the british style of uniform as part of westernising the Royal Thai Army for many reasons red is the cheapest dye colour, red is the background of the Siamese flags as well as the army colours. The piece which is played is call Rajawallop or Royal Guards March since their are the Royal Guards it is logical for them to play the song.