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 North African campaign of World War II took place in North Africa from 10 June 1940 to 13 May 1943. It included campaigns fought in the Libyan and Egyptian deserts, in Morocco and Algeria, and in Tunisia. The campaign was fought between the Allies and the Axis Powers. The Allied war effort was dominated by the British Commonwealth and exiles from German-occupied Europe. The United States officially entered the war in December 1941 and began direct military assistance in North Africa on 11 May 1942.
The South-East Asian Theatre of World War II consisted of the campaigns of the Pacific War in the Philippines, Thailand, Indonesia, Indochina, Burma, India, Malaya and Singapore between 1941 and 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.
Almost every country in the world participated in World War II. Most were neutral at the beginning, but only a relative few nations remained neutral to the end. The Second World War pitted two alliances against each other, the Axis powers and the Allied powers. It is estimated that 74 million people died, with estimates ranging from 40 million to 90 million dead. The leading Axis powers were Nazi Germany, the Empire of Japan and the Kingdom of Italy; while the United Kingdom, the United States, the Soviet Union and China were the "Big Four" Allied powers.
Middle East Command, later Middle East Land Forces, was a British Army Command established prior to the Second World War in Egypt. Its primary role was to command British land forces and co-ordinate with the relevant naval and air commands to defend British interests in the Middle East and eastern Mediterranean region.
The Glider Pilot Regiment was a British airborne forces unit of the Second World War, which was responsible for crewing the British Army's military gliders and saw action in the European theatre in support of Allied airborne operations. Established during the war in 1942, the regiment was disbanded in 1957.
The Allies, formally referred to as the United Nations from 1942, were an international military coalition formed during World War II (1939–1945) to oppose the Axis powers. Its principal members by the end of 1941 were the "Big Four" – the United Kingdom, United States, Soviet Union, and China.
The history of Canada during World War II begins with the German invasion of Poland on 1 September 1939. While the Canadian Armed Forces were eventually active in nearly every theatre of war, most combat was centred in Italy, Northwestern Europe, and the North Atlantic. In all, some 1.1 million Canadians served in the Canadian Army, Royal Canadian Navy, Royal Canadian Air Force, out of a population that as of the 1941 Census had 11,506,655 people, and in forces across the empire, with approximately 42,000 killed and another 55,000 wounded. During the war, Canada was subject to direct attack in the Battle of the St. Lawrence, and in the shelling of a lighthouse at Estevan Point on Vancouver Island, British Columbia.
The 78th Infantry Division, also known as the Battleaxe Division, was an infantry division of the British Army, raised during the Second World War that fought, with great distinction, in Tunisia, Sicily and Italy from late 1942–1945.
The 76th Infantry Division was an infantry division of the British Army, which was formed in November 1941 and served during the Second World War. It was created when the Norfolk County Division, initially raised in 1940 to defend the Norfolk coast from a potential German invasion, was redesignated. The division maintained the defensive duties that had been assigned to it, prior to it being renamed, until late 1942 when it became a training formation. It was then responsible for providing final tactical and field training to soldiers who had already passed their initial training. After five additional weeks of training, the soldiers were posted to fighting formations overseas. The formation was used as a source of reinforcements for the 21st Army Group, that was fighting in the Normandy campaign. After all available British troops had left the United Kingdom for France, the division was disbanded in September 1944.
The 61st Infantry Division was an infantry division of the British Army, raised in 1939 as part of the expansion of the Territorial Army in response to the German occupation of Czechoslovakia. The division was created as a duplicate of the 48th Infantry Division, and was assigned to home defence duties.
The Allied leaders of World War II listed below comprise the important political and military figures who fought for or supported the Allies during World War II. Engaged in total war, they had to adapt to new types of modern warfare, on the military, psychological and economic fronts.
At the beginning of World War II, Iceland was a sovereign kingdom in personal union with Denmark, with King Christian X as head of state. Iceland officially remained neutral throughout World War II. However, the British invaded Iceland on 10 May 1940. On 7 July 1941, the defence of Iceland was transferred from Britain to the United States, which was still a neutral country until five months later. On 17 June 1944, Iceland dissolved its union with Denmark and the Danish monarchy and declared itself a republic, which it remains to this day.
When the United Kingdom declared war on Nazi Germany in September 1939 at the start of World War II, it controlled to varying degrees numerous crown colonies, protectorates, and India. It also maintained strong political ties to four of the five independent Dominions—Australia, Canada, South Africa, and New Zealand—as co-members of the then "British Commonwealth". In 1939 the British Empire and the Commonwealth together comprised a global power, with direct or de facto political and economic control of 25% of the world's population, and of 30% of its land mass.
At the start of 1939, the British Army was, as it traditionally always had been, a small volunteer professional army. At the beginning of the Second World War on 1 September 1939, the British Army was small in comparison with those of its enemies, as it had been at the beginning of the First World War in 1914. It also quickly became evident that the initial structure and manpower of the British Army was woefully unprepared and ill-equipped for a war with multiple enemies on multiple fronts. During the early war years, mainly from 1940 to 1942, the British Army suffered defeat in almost every theatre of war in which it was deployed. But, from late 1942 onwards, starting with the Second Battle of El Alamein, the British Army's fortunes changed and it rarely suffered another defeat.
The Eighth Army was a field army of the British Army during the Second World War. It was formed as the Western Army on 10 September 1941, in Egypt, before being renamed the Army of the Nile and then the Eighth Army on 26 September. It was created the better to control the growing Allied forces based in Egypt and to direct their efforts to lift the siege of Tobruk via Operation Crusader.
The First Canadian Army was a field army and a formation of the Canadian Army in World War II in which most Canadian elements serving in North-West Europe were assigned. It served on the Western Front from July 1944 until May 1945.
The 1st Division was an infantry division of the British Army that was formed and disestablished numerous times between 1809 and the present. It was raised by Lieutenant-General Arthur Wellesley for service in the Peninsular War. It was disestablished in 1814 but re-formed the following year for service in the War of the Seventh Coalition and fought at the Battle of Waterloo. It remained active in France until 1818, when it was disbanded. It was subsequently raised for service in the Crimean War, the Anglo-Zulu War, and the Second Boer War. In 1902, it was re-raised in the UK. This latter event saw the division raised as a permanent formation, rather than being formed on an ad hoc basis for any particular crisis.