This is a list of military conflicts, involving the United Kingdom in the 20th century.
For the criteria of what may be permitted on this list, see List of wars involving the United Kingdom.
Key
20th-century wars
Conflict Allies Opponent(s) OutcomeWar of the Golden Stool(1900)British victory Capture of Yaa Asentawaa and banishment to the Seychelles Ashanti territories become part of Gold Coast colony in 1902 Ashanti retain control of the Golden Stool Somaliland campaign(1900–1920) (1900–1904) Dervish MovementBritish victory Mahsud Waziri blockade(1900–1902)
Mahsud rebelsBritish victoryIbn Rashid's invasion of Kuwait (1901) Kuwait Emirate of Ha'ilBritish victory Ottoman sultan orders end to siege Anglo-Aro War(1901–1902) Aro ConfederacyBritish victory Aro Confederacy destroyed Kano–Sokoto Expedition(1903) Battle of Kano Battle of Kwatarkwashi Battle of Burmi
Sokoto Caliphate Kano EmirateBritish victory British expedition to Tibet(1903–1904)
TibetBritish victory Convention of Lhasa Status quo ante bellum Bambatha Rebellion(1906)
Zulu rebelsBritish victory Bazar Valley campaign(1908)
Rebel tribesBritish victory Muscat Rebellion(1913–1920) Muscat and Oman Imamate of OmanInconclusive or other outcome First World War(1914–1918) Allied Powers
Other Allies Central Powers
German EmpireBritish Allied victory Treaty of Versailles: German demobilisation Treaties of Saint-Germain-en-Laye and Trianon: Demise of Austria-Hungary Russia pulls out in 1917 Russian Civil War Creation of the Soviet Union Creation of League of Nations: Mesopotamia ceded from the Ottoman Empire Palestine and Jordan ceded from the Ottoman Empire Tanganyika ceded from Germany Part of Kamerun ceded from Germany Part of Togoland ceded from Germany German New Guinea ceded to Australia German Samoa ceded to New Zealand German South West Africa ceded to South Africa Operations in the Tochi(1914–1915)
Khost tribesmenBritish victory Chilembwe uprising(1915)
Nyasaland Nyasaland rebelsBritish victorySecond Saudi-Rashidi War (1915–18) British Empire Nejd and Hasa Jabal Shammar
Ottoman EmpireInconclusive or other outcome Kelantan Rebellion(1915) British Empire British Malaya Kelantanese rebelsBritish victory Uprising suppressed Peshawar campaign(1915)
Mohmands, Bunerwals and SwatisBritish victory Bussa Rebellion(1915)
Bussa rebelsBritish victory Rebellion suppressed Invasion of Darfur(1916)
Sultanate of DarfurBritish Allied victory Easter Rising(1916)
Irish Citizen Army Irish Volunteers Fianna ÉireannCumann na mBanHibernian RiflesBritish victory Uprising suppressed Mohmand Blockade(1916–1917)
MohmandsBritish victory Mahsuds campaign(1917)
Mahsud tribesmenBritish victory Kuki Rebellion of 1917–1919(1917–1919)
Kuki tribesBritish victoryViena expedition (1918) Russian SFSR Red Guards White GuardRed–allied victory Adubi War(1918) British forces Egba rebelsBritish victory Uprising suppressed Estonian War of Independence(1918–1920) White movement Baltic German volunteers Danish volunteers Finnish volunteers Swedish volunteers
Baltische LandeswehrBritish Allied victory Independence of Estonia Vidzeme gained by the Republic of Latvia Latvian War of Independence(1918–1920) White movement West Russian Volunteer ArmyBritish Allied victory Independence of Latvia Allied intervention in the Russian Civil War(1918–1920) White movement
France
Latvian SSR Ukrainian SSR Commune of Estonia Mongolian Communists Bolshevik victory Allied withdrawal from Russia Bolshevik victory over White Army Establishment of the Soviet Union Irish War of Independence(1919–1921)
Irish RepublicInconclusive/Other Anglo-Irish Treaty Irish Free State established comprising the 26 counties of the formerly proposed Southern Ireland 6 counties of Northern Ireland remain part of UK with some violence continuing after the treaty United Kingdom retains the Ports of Berehaven, Spike Island and Lough Swilly Anglo-Yemeni War(1919–1934) Inconclusive/Other Treaty of Sanaa Yemen annexes Baidah, Na'wah, Rubeaten, and Juban Britain retains control over the Aden Protectorate Third Anglo-Afghan War(1919)
Disputed/Unknown Treaty of Rawalpindi Turkish War of Independence(1919–1923) (in 1920) (until 1922) Kuva-yi Inzibatiye (in 1920) Georgia (in 1921) Turkish National Movement Grand National Assembly (after 1920) Kuva-yi Nizamiye Kuva-yi Milliye (until 1920) Supported by: Azerbaijan SSR Georgian SSR Bukharan PSR Afghanistan All-India Muslim League Turkish Allied victory Treaty of Lausanne Overthrow of the Ottoman sultanate Withdrawal of Allied forces from occupied lands of Turkey Establishment of the Republic of Turkey Starting of the series of reforms led by Atatürk Kuwait–Najd War(1919–1920) Kuwait
Sultanate of Nejd IkhwanBritish Allied victory Waziristan campaign(1919–1920)
WaziristanBritish victory Samakh Raid(1920)
Arab Kingdom of SyriaSyrian victory Capture of Samakh Great Iraqi Revolution(1920) Iraqi rebelsBritish victory Greater autonomy given to Iraq Faysal ibn Husayn installed as King British Mandate for Mesopotamia cancelledPersian coup d'état (1921)Persian Cossack BrigadeAnti–Qajar victory Deposition of the Qajar dynastyWaziristan campaign (1921–1924) WaziristanBritish victory Burao tax revolt(1922)
Habr Yoonis tribesmenHabr Yoonis tribesmen victory Tax policy abandoned IRA Northern Offensive(1922)
Irish Republican ArmyBritish victory Adwan Rebellion(1923) Emir Abdullah's forces Hashemite allied tribesmen: Sheykh Minwar al-Hadid Sultan al-Adwan's forcesBritish Allied victory Sultan al-Adwan's defeat and exilePink's War (1925)MahsudBritish victory Wanhsien incident(1926)
Republic of ChinaInconclusive or other outcome Irene incident(1927)
PiratesBritish victory Ikhwan Revolt (1927–1930) Kuwait Nejd and Hejaz RAF Ikhwan British Allied victory Ikhwan attack on Kuwait repelled. The remnants of the Ikhwan incorporated into regular Saudi units. The Ikhwan leadership was either slain or imprisoned.Alfridi Redshirt Rebellion (1930-1931) AfridiBritish victory Objectives achievedMohmand campaign (1935) Mohmand Kingdom of AfghanistanBritish victory Revolt suppressed Great Arab Revolt in Palestine(1936–1939)
Palestine Police Force Jewish Settlement Police Jewish Supernumerary Police Special Night Squads NDF (from 1937) Arab "peace bands"
Jewish National Council Haganah Fosh Peulot Meyuhadot Irgun Arab Higher Committee (1936 – October 1937) Local rebel factions (fasa'il) Volunteers from Arab world Central Committee of National Jihad in Palestine (October 1937 – 1939) Bureau of the Arab Revolt in Palestine (late 1938 – 1939) Society for the Defense of PalestineRevolt suppressed Issuance of the White Paper of 1939 Waziristan Campaign(1936–1939)
WaziristanBritish victory Palestine Emergency(1939–1948) United Kingdom British Army Royal Navy Royal Air Force Royal Marines Palestine Police Force Jewish National Council Irgun (1944–1948) Lehi (1944–1948) Haganah (1945–1946) Palmach Hish Him Zionist victoryCharters, David A. The British Army and Jewish Insurgency in Palestine, 1945–47. Springer, 1989, p. X British forces unable to suppress insurgencyHoffman, Bruce. Inside Terrorism. Columbia University Press, New York, pp. 49–51 Insurgency turned British public opinion against the deployment in Palestine, leading to Britain deferring the issue to the United Nations Start of civil war in Mandatory Palestine in response to the UN Partition Plan S-Plan16 January 1939 – March 1940 Irish Republican ArmyBritish victoryCrowley, pg 809 British victory IRA failed to force the withdrawal of British troops from Ireland Second World War(1939–1945) Allied Powers
France Poland
Gorkha Kingdom Axis PowersBritish Allied victory Nazi Germany formally surrenders 8 May 1945, ending the Second World War in Europe. On 15 August 1945, following the dropping of atom bombs on Hiroshima and Nagasaki, Japan announces its surrender, ending the Second World War. British (and Commonwealth), French, American, and Soviet troops occupy Germany until 1955 Italy and Japan lose their colonies Europe is divided into 'Soviet' and 'Western' spheres of interest.Continuation War (1941 – 1944)Soviet–allied victory Moscow Armistice Anglo-Soviet Invasion of Iran(1941)
British–allied victoryNorthern Campaign(2 September 1942 – December 1944) Royal Ulster Constabulary Irish Republican ArmyBritish victory IRA campaign failureWoyane rebellion(May – November 1943) Woyane rebelsAnglo-Ethiopian victoryAfghan tribal revolts of 1944–1947(1944–1947)Allied Nuristani tribesmenRebel tribes: Zadran Mangal SafiAfghan government & British victory Rebel invasion of India in 1944 repelled Rebels fully defeated by Afghan government in January 19471944–45 Insurgency in Balochistan(1944–1945)Badinzai rebelsBritish victory Insurgency subsided by March 1945 Dekemvriana(1944–1945) Kingdom of Greece National Liberation Front (Greece) ELASBritish–allied victoryConquest of al-Ghurfa(1945)Al-GhurfaBritish victory 1945 Sheikh Bashir Rebellion (1945)
Armed Habr Je'lo tribesmen British victorySheikh Bashir killed, unrest continues, anti-colonialist and nationalist sentiment increases in Somaliland Indonesian National Revolution(1945–1949)
(until 1945) Indonesia (volunteers) (defectors)Inconclusive or other outcome Hand over to Dutch in 1946 Netherlands recognises Indonesian Independence Operation Masterdom(1945–1946)
France Empire of Japan Việt MinhBritish Allied victory Hand over to French First Indochina War begins Greek Civil War (1946–1948)
D.S.E. (Δ.Σ.Ε.)British Allied victoryCommunist forces defeated, many D.S.E. soldiers exiled in Eastern Europe.Battalion of UK troops still in Greece until 1948 Corfu Channel incident(1946–1948)
Inconclusive or other outcome World Court case concluded in 1949 Britain breaks off talks aimed at establishing diplomatic relations with Albania. 1947–1948 civil war in Mandatory Palestine(1947–1948)
Jewish National Council Haganah Palmach Irgun Lehi Foreign volunteers Allied Bedouin tribes
Arab Higher Committee Army of the Holy War Arab Liberation Army
Arab LegionJewish National Council victory Issuance of the Israeli Declaration of Independence Intervention by neighbouring Arab states, beginning the 1948 Arab–Israeli War 1948 Palestine war(1947–1949)
(before 15 May 1948)
Yishuv(before 14 May 1948)(after 14 May 1948) Before 26 May 1948: Haganah Palmach Hish Corps HIM Corps Irgun Lehi Druze militants Allied Bedouin tribesPalestine Post, "Israel's Bedouin Warriors", Gene Dison, August 12, 1948
After 26 May 1948: Israel Defense Forces Sword Battalion
Foreign volunteers: Mahal
Arab Higher Committee(before 15 May 1948)(after 15 May 1948)
Arab Liberation Army Holy War Army Al-Najjada Egypt All-Palestine Protectorate (after 22 Sep 1948) Transjordan Syria Iraq
Israeli victory 1949 Armistice Agreements: Establishment of the State of Israel Occupation of the Gaza Strip by Egypt and establishment of the All-Palestine Government Annexation of the West Bank by Jordan (including East Jerusalem) Syrian foothold established to the north and south of the Sea of GalileeBerlin Blockade(1948-1949)Western Allied victory Blockade lifted West Berlin remains under the control of the Western Allies Malayan Emergency(1948–1960) British Commonwealth
Federation of Malaya
Malayan Communist Party Malayan National Liberation ArmyBritish Allied victory Destruction of the majority of MNLA guerrilla organisations, Communist leadership retreat to Thailand Preservation of capitalism and British economic interests Operation Valuable(1949–1956) MI6
CIA
DGSE
Italy West Germany Kingdom of Greece Turkey
KEVA
Yugoslavia
Albanian Victory Failure to overthrow the communist government of Enver Hoxha