Malaya Straits Settlement Post in Bangkok, Scott 10, SG 11. BANGKOK, 1882, 96c Olive Gray. The British Post Office in Bangkok came about in May 1882 due to the level of demand, mainly from merchants, and was stationed within their consulate. Prior to this, mail was sent via diplomatic pouches to Singapore (Straits Settlements) where the letters were placed in the mail. This continued until 1885 when Siam joined the U.P.U. and assumed mail functions.