Declarations of war by Great Britain and the United Kingdom - wikipedia Declarations of war by Great Britain and the United Kingdom A declaration of war is a formal declaration issued by a national government indicating that a state of war exists between that nation and another. In the United Kingdom, only the monarch has the power to declare war and peace, under the royal prerogative. There have been no declarations of war since the Second World War, though British Armed Forces have taken part in armed conflict on numerous occasions nonetheless. There has been a long - running debate regarding whether Parliament alone should have the power to declare war and more widely to commit British forces to armed conflict. This was attempted ( to the limited extent of possible war against Iraq ) in 1999 with the introduction of the Military Action Against Iraq ( Parliamentary Approval ) Bill. However Queen Elizabeth II, acting upon the advice of her government at the time, refused to grant her consent to allow the bill to be debated in Parliament and so it was dropped ( Queen 's Consent was needed before debate could take place because the bill affected the royal prerogative ). The Constitutional Reform and Governance Act 2010 originally included a section that would have required Parliamentary approval for use of the armed forces, but this was dropped from the bill before royal assent. Contents 1 Formal declarations of war by the Kingdom of Great Britain 2 Formal declarations of war by the United Kingdom 3 See also 4 Notes and references 5 External links Formal declarations of war by the Kingdom of Great Britain See also : List of wars involving Great Britain The following table refers to declarations of war from the Act of Union in 1707 until the creation of the United Kingdom of Great Britain and Ireland in 1801. This list is incomplete ; you can help by expanding it. War or conflict Opponent ( s ) Initial authorisation Declaration Monarch Prime Minister Conclusion War of the Quadruple Alliance Spain 17 December 1718 George I None Treaty of The Hague, 17 February 1720. War of Jenkins ' Ear Spain 23 October 1739 George II Robert Walpole Treaty of Aix - la - Chapelle, 18 October 1748. War of the Austrian Succession France 31 March 1744 Henry Pelham Seven Years ' War France 17 May 1756 Declaration on France Thomas Pelham - Holles Treaty of Paris, 10 February 1763. British victory. Spain 4 January 1762 Declaration on Spain George III American Revolutionary War France 17 March 1778 Declaration on France Lord North Treaty of Versailles, 3 September 1783. Spain 1779 Declaration on Spain Treaty of Versailles, 3 September 1783. Fourth Anglo - Dutch War Dutch Republic December 1780 Declaration on the Dutch Republic Treaty of Paris, 20 May 1784. Formal declarations of war by the United Kingdom See also : List of wars involving the United Kingdom The following table refers to declarations of war since the creation of the United Kingdom in 1801. In 1927 the United Kingdom of Great Britain and Ireland was renamed the `` United Kingdom of Great Britain and Northern Ireland ''. This list is incomplete ; you can help by expanding it. War or conflict Opponent ( s ) Initial authorisation Declaration Monarch Prime Minister Conclusion Napoleonic Wars France 18 May 1803 George III Henry Addington Crimean War Russia 28 March 1854 Declaration on the Russian Empire Victoria Earl of Aberdeen Treaty of Paris, 30 March 1856 Anglo - Zulu War Zulu tribe 11 January 1879 Ultimatum by Sir Henry Bartle Frere Benjamin Disraeli The war ended the Zulu nation 's independence. First World War Germany 4 August 1914 Declaration on Germany George V H.H. Asquith Armistice with Germany, 11 November 1918. Treaty of Versailles, 28 June 1919. Austria - Hungary 12 August 1914 Declaration on Austria - Hungary Austria : Treaty of Saint - Germain - en - Laye, 10 September 1919. Hungary : Treaty of Trianon, 4 June 1920. Ottoman Empire 5 November 1914 Declaration on the Ottoman Empire Treaty of Sèvres, 10 August 1920. Bulgaria 15 October 1915 Declaration on Bulgaria Treaty of Neuilly - sur - Seine, 27 November 1919. Second World War Germany 3 September 1939 British and French declaration of war on Germany George VI Neville Chamberlain Treaty on the Final Settlement with Respect to Germany, 12 September 1990. The Potsdam Agreement on 2 August 1945 agreed the subdivision of Germany following the surrender on 8 May 1945. Austria was part of Germany when War was declared, and was formally re-established by the Treaty of Vienna on 15 May 1955. Italy 11 June 1940 Declaration on Italy Winston Churchill Armistice with Italy, 3 September 1943. The final peace treaty between Italy and the Allies was signed in Paris on 10 February 1947. Finland 6 December 1941 Declaration on Finland Moscow Armistice, 19 September 1944. The final peace treaty between Finland and the Allies was signed in Paris on 10 February 1947. Hungary 6 December 1941 Declaration on Hungary The final peace treaty between Hungary and the Allies was signed in Paris on 10 February 1947. Romania 6 December 1941 Declaration on Romania Armistice with Romania, 12 September 1944. The final peace treaty between Romania and the Allies was signed in Paris on 10 February 1947. Japan 8 December 1941 Declaration on Japan Treaty of San Francisco, 8 September 1951. This followed the Surrender of Japan on 15 August 1945 and the Occupation of Japan which began on 28 August 1945. Bulgaria 13 December 1941 Declaration on Bulgaria Armistice with Bulgaria, 28 October 1944. The final peace treaty between Bulgaria and the Allies was signed in Paris on 10 February 1947. Thailand 25 January 1942 Declaration on Thailand Anglo - Thai Peace Treaty, 1 January 1946 See also Declaration of war Undeclared war List of wars involving Great Britain Declaration of war by Canada Declaration of war by the United States Constitution of the United Kingdom Notes and references Jump up ^ The Governance of Britain - War powers and treaties : Limiting Executive powers, The Stationery Office, 2007 - 10 - 25. Retrieved on 2009 - 03 - 15 Jump up ^ Norton - Taylor, Richard Former defence chiefs oppose role for MPs in war decisions, The Guardian. 2007 - 12 - 28. Retrieved on 2009 - 03 - 15 Jump up ^ Kettle, Martin A declaration of war on this medieval royal prerogative, The Guardian. 2005 - 08 - 23. Retrieved on 2009 - 03 - 15 ^ Jump up to : https://publications.parliament.uk/pa/cm199899/cmhansrd/vo990723/debtext/90723-23.htm External links War Powers and Treaties : Limiting Executive Powers ( pub. October 2007 ( accessed on 2016.10. 09 ) Retrieved from `` https://en.wikipedia.org/w/index.php?title=Declarations_of_war_by_Great_Britain_and_the_United_Kingdom&oldid=798074480 '' Categories : Wars involving the United Kingdom Wars involving Great Britain Declarations of war Constitution of the United Kingdom Foreign relations of the United Kingdom Hidden categories : Incomplete lists from February 2011 Talk Contents About Wikipedia Add links This page was last edited on 30 August 2017, at 20 : 47. Text is available under the Creative Commons Attribution - ShareAlike License ; additional terms may apply. By using this site, you agree to the Terms of Use and Privacy Policy. Wikipedia ® is a registered trademark of the Wikimedia Foundation, Inc., a non-profit organization. About Wikipedia

Question: who decides if we go to war uk
Answer: monarch