The British-Siamese War was a war over Kedah fought by Britain and Siam in 1874. It ended in the the victory of the Royal Siamese Army and the annexation of modern day Malaya.
Siam (Thailand) declared war on Britain when British forces raided a village. Britain, which was on the peak of its imperialism, attempted to force Siamese authorities to withdraw through the "Siamese Gunboat Incident", but failed to. After this failure, Thai forces under Prince Dawongrose launched an offensive into Kedah and defeated British forces during the battle of Kuah. British forces further retreated down into modern day Malaya, but was forced out after another decisive defeat Kuala Kedah.
Before 1874, Siam had received help from both Britain and France to help modernize it's armed forces. Modernization was achieved in 1869, when Prince Dawongrose, on the behalf of King Chulalongkorn, established the Royal Siamese Armed Forces. Introducing universe conscription, it had become a fledgling army by 1871. Having around 250,000 active soldiers (both from the navy and the army), organized into four armies and two fleets, and with 450,000 men ready for action by 1874, Thailand was well prepared for this war. Meanwhile, Britain had few reinforcements, but still had a formidable position in Malaya. With 90,000 British troops and Malayan levies in 1874, it had presented a formidable task for the Royal Siamese Army. However, the Royal Navy was superior to the Royal Thai Navy.With 14 Ironclads ready for action at anytime, the Royal Navy presented a challenge to the largely wooden Siamese fleet. With only 12 Ironclads in the whole navy, Siam had 25 Iron Frigates and 31 4-Deckers. However, Siamese commanders, most notably Prince Abhakara Kiartivongse (whom had been trained in Britain), had more common sense than the British commanders.
Incidents leading up to the war
After a raid on a small Siamese village by Malaysian levies, the Siamese government asked for a "a good explanation or else it's war" British authorities in Malaysia, asked by the throne to avoid war with Siam, said "it was a mistake. You should forget about it." Siam replied via telegram, saying that "Is that all you're going to say?" British authorities replied with a simple "Yes". Then without any declaration of war, Britain attacked Narathiwat. The Royal Siamese Army, caught unprepared, deployed its Central and Southern army to fight the British.
The Siamese Gunboat Incident
While the Central and Southern Army was travelling down to Narathiwat, the Royal Siamese Navy ordered the evacuation of citizens around coastal areas. King Chulalongkorn, who was in Laos at the time, sent telegrams to France and Japan, asking for help if the war gets out of control. Japan accepted it, as the young Emperor knew King Chulalongkorn very well in his travels. France also accepted, as the Louis Napoleon knew that British victory in the Malayas would threaten there possessions. On the 21st of December, 1874, a fleet of six British Ironclads appeared in the Gulf of Thailand. The Royal Siamese Navy dispatched four French Built Ironclad and seven Frigates to deal with the fleet. This resulted in a fierce naval war. The Siamese Ironclad Chaloern and Mongkut, the leaders of the fleet, fired and destroyed the George IV, the center ironclad. As the British maneuvered to get their broadside guns to fire on the Siamese ships, a Siamese frigate, Chao Phraya, fired a lucky shot that destroyed the Elizabeth. The loss of the Elizabeth was shadowed by the emergence of 4 Siamese 4-Deckers from the rear. Surrounded, the Ironclad fleet attempted to fight it's way out, but failing after the Mongkut destroyed the Monarch. Having no choice but to surrender, the Ironclad fleet struck the colours. This had been a decisive victory to the Siamese forces. The Siamese lost 165 men and 463 had been wounded. The British lost 193 men, with the rest of the 650 men fleet captured, but losing the rest of their three ironclads.
Battle of Kuah
After the victory of the Royal Siamese Navy, the Royal Siamese Army arrived in Narathiwat on December 25th, 1874 to find that British troops had pulled out. Ordered to resume the fighting, Prince Dawongrose advanced down to Kedah, where British forces had constructed a line. British troops at Kedah were armed with Snider Enfields, while Siamese troops were armed with Minie rifles from France. Prince Dawongrose ordered a artillery bombardment from the Siamese Artillery Brigade, which was trained by the French. The British Commander, Maj.Gen. Douglas Mobley, ordered a series of accurate counter fire back to the Siamese artillery. After a series of highly accurate and mutually destructive artillery fire, both sides waited for each other to start the battle. Prince Dawongrose took this opportunity to fortify his troops for a British attack, while Maj.Gen Douglas Mobley prepared his troops for an counter offensive. The Siamese forces were reinforced with three Gatling guns and 12 field guns. Not knowing the fact that the Siamese had been reinforced with them, British cavalry attacked the Siamese right flank. However, the Gatling guns and the field guns opened fire on the cavalry, pushing them back. The Siamese then took the offensive and attacked the left. British gunfire caused heavy casualties on the Siamese, but sheer Siamese numbers meant the British pulled back. Siamese troops then launched a series of offensive on the center. After heavy casualties in the fighting, Prince Dawongrose ordered his reserves the offensive on the British Left, as most British troops were redeployed to the center. Putting Gatling guns on elephants, Thai forces were able to break the British left. As the left had all the escape routes (from land), the British forces was effectively surrounded. Several breakout attempts were launched, but failing to break the Siamese line. Douglas then consulted his superiors via telegram, and surrendered. Siam lost 4561 men, with 52,041 wounded and 56 missing (out of the 50,000), while the British lost 6531 men, with 65,245 wounded and 41,234 captured, with 103 missing (out of the 25,000).
Battle of Kuala Kedah
After another Siamese victory at Kedah, Sir John Bowring was sent to Siam to negotiate terms, but the war continued down south. Prince Dawongrose, after defeating the British at Kuah, decided to destroy the last British garrisons in Kedah. The Siamese forces, under the cover of night, surrounded the British forts. Armed with Minie rifles, the Siamese forces attacked the British during dawn of the next day. British Commander Charles Moore, surprised at this attacked, ordered his British force to regroup on top of the Kuala Kedah hill. British forces fought desperately and stubbornly, but when the Siamese received reinforcements of four Gatling guns and five field guns, the British were doomed. As the British made a desperate last stand on the hill, Prince Dawongrose ordered his artillery to release it's wrath. The British made desperate maneuvers, but failed. Charles Moore ordered a withdrawal of all the wounded through the last escape route. 4245 British soldiers made it through, but a total of 12,000 didn't. Determined to destroy the British, Prince Dawongrose had ordered his reserves up, making the total number of Siamese forces number up to (according to some estimates) 120,000. Surrounding the British, he ordered a head on assault. Losing tremendous amounts of lives to British gunfire, the British finally surrendered its remaining 300 men. The Siamese lost a total of 13,503 men, with 65,021 wounded (of the 120,000), while the British lost 14,322 men, with 4320 wounded and 302 captured (of the force of 20,000).
Battle of Koh Chang and the Treaty of Bangkok
Koh Chang became a naval base for this war. When Britain knew this, they ordered the remainder of the fleet of ten Ironclads to destroy the base. The Siamese Naval base on Koh Chang included a battery of 150mm field guns brought in from France, and three Ironclads (plus six 4-deckers and five Frigates). Britain had failed in the element of surprise, as Siamese fisherman had reported the ships. However, the Siamese Navy had only ordered reinforcements the day when the British approached Koh Chang. Siamese resistance was stubborn, as the British attempted to land marines on Koh Chang. Admiral Wong Luksadi, commander of the ships at Koh Chang, ordered his ships to meet the British fleet in a head to head battle. He failed to defeat the British as he failed to deploy all three ironclads. However, when the British arrived within firing range of the gun batteries, they were in trouble. As the Siamese Gun batteries fired, the British received intelligence of a large Siamese fleet (the fleet consisted of four Ironclads, six Frigates, and 12 4-Deckers, but the British commander, John Wolesley, told the fleet that it consisted of nine Ironclads, 12 Frigates and 19 4-Deckers). Withdrawing, the Battle of Koh Chang was the only British victory of the war, and it was to have an effect on British gains from this. Sir Bowring, after meeting with King Chulalongkorn, concluded that Malaya would have to be given up. However, he said that "A small part of Malaya shall continue to be British" (He talked about Singapore, which continued to be British up to the 1960s). The Treaty of Bangkok effectively ended British ambitions in South East Asia.
Britain never again seriously challenged Siam until World War II, during the British-Thai War, but was also defeated by a joint Japanese Thai force. Meanwhile, Modern-Day Malaya (except for Singapore) was given to Siam, and Siam effectively gained the support of Japan and the US to keep Laos, which became independent in 1967. Siam has proven to the world that a fledgling modernized nation could (and should) resist imperialism. This also sparked some Nationalist-Socialistic behaviour in the Siamese populace. This led to the 1932 Rebellion. Siam, in this war, lost 4000 men, with 10,000 wounded and 450 missing (the Navy lost one Ironclad and five 4-deckers), while Britain lost 13,000 men, with 25,000 more wounded and 12,000 captured (the Navy lost six Ironclads).