Rejecting a solution to the Laotian problem by peaceful means, the French in 1893, strengthened by gunboat diplomacy, forced the Thais to renounce all claims to all territory on the east bank of the Mekong and to all islands in that river.
Although Thailand complied with all French demands promptly, the French continued to occupy Channtabun(Chanthaburi), which had a greater strategic importance. In order to terminate this occupation, King Chulalongkorn signed the Convention of 1904, by which Thailand ceded further territories on the west bank of the Mekong.
King Chulalongkorn’s policy of territorial concession was not able to stop France’s territorial advance. The French moved out from Chanthaburi to occupy the nearby town of Trat, where their nuisance value was as high as ever. To terminate France’s occupation of Trat, King Chulalongkorn signed the treaty of 1909, ceding to France the provinces of Battambang and Siemreap.
King Chulalongkorn’s failure to maintain Thailand’s territorial integrity owed much to his failure to engage another power to counter-balance France. The king asked for diplomatic and military assistance from Great Britain. But the latter did not consider Thai possessions in Laos and Cambodia worth the risk of war with France. During the Franco-Thai political crisis, London on several occasions urged the decision-makers in Bangkok not to hesitate to yield to French demands.
After the end of the Franco-Thai political crisis, King Chulalongkorn still hoped to use Britain to counter-balance France. This was evident in his intention to further strengthen friendly relations with Great Britain. In 1909 he voluntarily ceded to Britain the four Malay provinces of Kelantan, Trengganu, Perlis and Kedah. The King also altered the country’s internal life to match of Great Britain.
Students sent abroad for advanced study usually went to England. The school system was a copy of the English system. The absence of text-books in the native language made it imperative to adopt a European language as the medium of higher education. English consequently became the second language used by educated Thais. Thailand’s financial policy and trade interests also leaned towards the British.
King Chulalongkorn clearly played the British and the French each other, while looking towards Russia, Japan, and Germany as possible alternative countervailing powers.