+ Country   : British Overseas Post Office
+ Sub-Area  : Bangkok, Siam
+ Class     : Stamp & Philatey
+ Prefix    : BPOBK
+ Σ Group   : 6
+ Σ Stamp   : 32
+ Σ Variety : 7
+ Σ Listing : Postage Stamp, Postcard Prepaid (With Indicia)

An overseas postal service for foreign residents was operated by the British Consulate at Bangkok from 1858. Mail was despatched by steamer to Singapore and from 1876 onwards was increasingly franked with Straits Settlements stamps. These were initially cancelled on arrival at Singapore, but late an oval postmark inscribed "BRITISH CONSULATE BANGKOK" was used. In 1883, a circular BANGKOK datestamp was introduced for use.

The use of these stamps ceased on 30 June 1885. Siam joined the Universal Postal Union on 1 July 1885.