The military history of the United Kingdom in World War II covers the Second World War against the Axis powers, starting on 3 September 1939 with the declaration of war by the United Kingdom and France, followed by the UK's Dominions, Crown colonies and protectorates on Nazi Germany in response to the invasion of Poland by Germany. There was little, however, the Anglo-French alliance could do or did do to help Poland. The Phoney War culminated in April 1940 with the German invasion of Denmark and Norway. Winston Churchill became prime minister and head of a coalition government in May 1940. The defeat of other European countries followed – Belgium, the Netherlands, Luxembourg and France – alongside the British Expeditionary Force which led to the Dunkirk evacuation in June 1940.
The Pacific War, sometimes called the Asia–Pacific War or the Pacific Theater, was the theater of World War II that was fought in eastern Asia, the Pacific Ocean, the Indian Ocean, and Oceania. It was geographically the largest theater of the war, including the Pacific Ocean theater, the South West Pacific theater, the Second Sino-Japanese War, and the Soviet–Japanese War in the last few months of the war.
The 11th Army Group was the main British Army force in Southeast Asia during the Second World War. Although a nominally British formation, it also included large numbers of troops and formations from the British Indian Army and from British African colonies, and also Nationalist Chinese and United States units.
The British Fourteenth Army was a multi-national force comprising units from Commonwealth countries during the Second World War. As well as British Army units, many of its units were from the Indian Army and there were also significant contributions from the British Army's West and East African divisions. It was often referred to as the "Forgotten Army" because its operations in the Burma campaign were overlooked by the contemporary press, and remained more obscure than those of the corresponding formations in Europe for long after the war. For most of the Army's existence, it was commanded by Lieutenant-General William Slim.
South East Asia Command (SEAC) was the body set up to be in overall charge of Allied operations in the South-East Asian Theatre during the Second World War.
The Burma campaign was a series of battles fought in the British colony of Burma. It was part of the South-East Asian theatre of World War II and primarily involved forces of the Allies against the invading forces of the Empire of Japan. Imperial Japan was supported by the Thai Phayap Army, as well as two collaborationist independence movements and armies. Nominally independent puppet states were established in the conquered areas and some territories were annexed by Thailand. In 1942 and 1943, the international Allied force in British India launched several failed offensives to retake lost territories. Fighting intensified in 1944, and British Empire forces peaked at around 1 million land and air forces. These forces were drawn primarily from British India, with British Army forces, 100,000 East and West African colonial troops, and smaller numbers of land and air forces from several other Dominions and Colonies. These additional forces allowed the Allied recapture of Burma in 1945.
China Burma India Theater (CBI) was the United States military designation during World War II for the China and Southeast Asian or India–Burma (IBT) theaters. Operational command of Allied forces in the CBI was officially the responsibility of the Supreme Commanders for South East Asia or China. In practice, U.S. forces were usually overseen by General Joseph Stilwell, the Deputy Allied Commander in China; the term "CBI" was significant in logistical, material and personnel matters; it was and is commonly used within the US for these theaters.
The American-British-Dutch-Australian (ABDA) Command, or ABDACOM, was the short-lived supreme command for all Allied forces in South East Asia in early 1942, during the Pacific War in World War II. The command consisted of the forces of Australia, the Netherlands, United Kingdom and the United States. The main objective of the command, led by General Sir Archibald Wavell, was to maintain control of the "Malay Barrier", a notional line running down the Malay Peninsula, through Singapore and the southernmost islands of the Dutch East Indies. ABDACOM was also known in British military circles as the "South West Pacific Command", although it should not be confused with the later South West Pacific Area command.
The Far East Command was a British military command which had 2 distinct periods. These were firstly, 18 November 1940 – 7 January 1942 succeeded by the American-British-Dutch-Australian Command (ABDACOM), and secondly, 1963–1971 succeeded by Australia, New Zealand, and United Kingdom Force
![<span class="mw-page-title-main">GHQ India</span> Headquarters of the [British] Indian Army](https://upload.wikimedia.org/wikipedia/commons/thumb/2/2e/GHQ_India.svg/320px-GHQ_India.svg.png)
General Headquarters, India was the headquarters of the Commander-in-Chief, India, who commanded the British military forces in India, including the British Indian Army, after the Kitchener Reforms of 1903. It succeeded Headquarters, India which was the term in use initially after the three Presidency armies had been amalgamated into one force. The Commander-in-Chief answered to the civilian Viceroy of India.
The Malayan campaign, referred to by Japanese sources as the Malay Operation, was a military campaign fought by Allied and Axis forces in Malaya, from 8 December 1941 – 15 February 1942 during the Second World War. It was dominated by land battles between British Commonwealth army units and the Imperial Japanese Army, with minor skirmishes at the beginning of the campaign between British Commonwealth and Royal Thai Police. The Japanese had air and naval supremacy from the opening days of the campaign. For the British, Indian, Australian, and Malayan forces defending the colony, the campaign was a total disaster.
Operation Dracula was a World War II-airborne and amphibious attack on Rangoon by British and Anglo-Indian forces during the Burma Campaign.
Force 136 was a far eastern branch of the British World War II intelligence organisation, the Special Operations Executive (SOE). Originally set up in 1941 as the India Mission with the cover name of GSI(k), it absorbed what was left of SOE's Oriental Mission in April 1942. The man in overall charge for the duration of its existence was Colin Mackenzie.
The Chinese Expeditionary Force was an expeditionary unit of China's National Revolutionary Army that was dispatched to Burma and India in support of the Allied efforts against the Imperial Japanese Army during the Japanese invasion and occupation of Burma in the South-East Asian theatre of the Second World War.
The Dutch East Indies campaign of 1941–1942 was the conquest of the Dutch East Indies by forces of the Empire of Japan in the early days of the Pacific campaign of World War II. Allied forces attempted unsuccessfully to defend the islands. The East Indies were targeted by the Japanese for their rich oil resources which would become a vital asset during the war. The campaign and subsequent three-and-a-half-year Japanese occupation was also a major factor in the end of Dutch colonial rule in the region.
The First Indian National Army was the Indian National Army as it existed between February and December 1942. It was formed with Japanese aid and support after the Fall of Singapore and consisted of approximately 12,000 of the 40,000 Indian prisoners of war who were captured either during the Malayan campaign or surrendered at Singapore. It was formally proclaimed in April 1942 and declared the subordinate military wing of the Indian Independence League in June that year. The unit was formed by Mohan Singh. The unit was dissolved in December 1942 after apprehensions of Japanese motives with regards to the INA led to disagreements and distrust between Mohan Singh and INA leadership on one hand, and the League's leadership, most notably Rash Behari Bose. Later on, the leadership of the Indian National Army was handed to Subhas Chandra Bose. A large number of the INAs initial volunteers, however, later went on to join the INA in its second incarnation under Subhas Chandra Bose.
The Japanese invasion of Burma was the opening phase of the Burma campaign in the South-East Asian theatre of World War II, which took place over four years from 1942 to 1945. During the first year of the campaign, the Japanese Army drove British Empire and Chinese forces out of Burma, then began the Japanese occupation of Burma and formed a nominally independent Burmese administrative government.
The Burma campaign in the South-East Asian Theatre of World War II took place over four years from 1942 to 1945. During the first year of the campaign, the Imperial Japanese Army with aid from Burmese insurgents had driven British forces and Chinese forces out of Burma, and occupied most of the country. From May to December 1942, most active campaigning ceased as the monsoon rains made tactical movement almost impossible in the forested and mountainous border between India and Burma, and both the Allies and Japanese faced severe logistical constraints.
The fighting in the Burma campaign in 1944 was among the most severe in the South-East Asian Theatre of World War II. It took place along the borders between Burma and India, and Burma and China, and involved the British Commonwealth, Chinese and United States forces, against the forces of Imperial Japan and the Indian National Army. British Commonwealth land forces were drawn primarily from the United Kingdom, British India and Africa.
The Burma campaign in the South-East Asian Theatre of World War II was fought primarily by British Commonwealth, Chinese and United States forces against the forces of Imperial Japan, who were assisted by the Burmese National Army, the Indian National Army, and to some degree by Thailand. The British Commonwealth land forces were drawn primarily from the United Kingdom, British India and Africa.
Portuguese Timor 
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Vichy France 
