Thailand

Thailand was nominally ruled by a council of regency, as the king, Ananta Mahidol, remained in Switzerland throughout the war. The real power lay with the country's C-in-C and prime minister, Field Marshal Pibul Songgram, a pro-Japanese military dictator. In June 1939 he changed the country's name from Siam. As thai means ‘free’ this did not please the British, who saw it as symbolic of Pibul's intentions of aligning his country against western colonial influence and co-operating with Japan.

The peacetime strength of the Thai army was 26,500 men organized into two corps; by November 1940 this number had risen to 50,000. The air force had 150 of varying types and age, plus 120 training aircraft. The navy had a British-built destroyer of First World War vintage, nine large, modern Italian-built torpedo boats, and a miscellany of smaller vessels. Two light cruisers were being built in Italy but these were commandeered by the Italians in December 1941.

In 1940, the two major colonial powers in South-East Asia, France and the UK, signed pacts of non-aggression with Thailand, which declared its neutrality. Despite this, in early 1941 Pibul attacked the French protectorates of Laos and Cambodia in French Indo-China to regain disputed border territories. Though victorious on land, Pibul lost at sea (battle of Koh-Chang, January 1941) and both sides accepted Japanese mediation. As a result the Vichy French administration in French Indo-China was forced to sign a treaty in May 1941 which gave Thailand the territories it claimed; and the Japanese southward advance against British and Dutch colonial territories then used French Indo-China and Thailand as staging-posts for its campaigns.

The first of these campaigns started in the early hours of 8 December 1941 when the Japanese landed on the Thai coast at Singora and Patani in order to facilitate their Malayan campaign. Initially, the Thais resisted, as they did a British advance from Malaya the same day, but on 9 December Pibul ordered all resistance to cease. On 25 January 1942 he declared war on the UK and USA, but not on China with whom Japan was also at war. The UK reciprocated, but the USA, believing the country was being coerced, did not, an early sign of policy differences which reflected American suspicions of British post-war intentions towards Thailand. ‘For the British, Siam had become, quite simply, an enemy country. For the Americans, who had not reciprocated Siam's declaration of war, she was an enemy-occupied country’ ( L. Allen, The End of the War in Asia, London, 1976, p. 32).

collaboration with the Japanese brought Thailand liberal awards of neighbouring territories. Following its declaration of war the Thai government was allowed to occupy the four northerly Unfederated States of Malaya, and when Burma was granted independence in August 1943 Thailand received the Shan states of Kengtun and Mongpan. But though outwardly compliant with the Japanese, many Thais were sympathetic to the Allies. Pibul's political rival, Nai Pridi Bhanomyong, had been made regent by Pibul to keep him quiet. But Pridi started a Free Thai Movement which later linked up with another resistance movement to become the ‘XO group’. This worked with SOE and with the Office of Strategic Services to foster resistance within Thailand, though the two Allied organizations reflected their countries' differing political attitudes towards Thailand by acting independently of one another. In July 1944 Allied successes and pressure from the Free Thai Movement resulted in the fall of Pibul's government. Khuang Aphaiwong now became prime minister of a government which followed Pridi and by August 1945, when Japan surrendered, local guerrillas had already been in control of northern Thailand for some months.

The terms on which the British were prepared to make peace with Thailand were regarded as too harsh by the Americans, who thought the UK was attempting commercial domination of the country. The USA backed the Thais who achieved the terms they sought. See also anti-imperialism and nationalism.