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.^[1] 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^[2][3] 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^[4] 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).^[4] 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.

Formal declarations of war by the Kingdom of 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.

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

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".

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

External links

• War Powers and Treaties: Limiting Executive Powers (pub. October 2007 (accessed on 2016.10.09)