His Majesty's Armed Forces, also known colloquially as the British Armed Forces, are the unified military forces responsible for the defence of the United Kingdom, its Overseas Territories and the Crown Dependencies. They also promote the UK's wider interests, support international peacekeeping efforts and provide humanitarian aid.The Mission of the Armed Forces , armedforces.co.uk
Since the formation of the united Kingdom of Great Britain in 1707 (later succeeded by the United Kingdom of Great Britain and Ireland in 1801, and finally by the United Kingdom of Great Britain and Northern Ireland in 1927), the British Armed Forces have seen action in most major wars involving the world's great powers, including the Seven Years' War, the Napoleonic Wars, the Crimean War, the First World War and the Second World War. Britain's victories in most of these wars allowed it to influence world events and establish itself as one of the world's leading military and economic powers. The British Armed Forces consist of: the Royal Navy, a blue-water navy with a fleet of 62 commissioned and active ships, together with the Royal Marines, a highly specialised amphibious light infantry force; the British Army, the UK's land warfare branch; and the Royal Air Force, a technologically sophisticated air force with a diverse operational fleet consisting of both fixed-wing and rotary aircraft. The British Armed Forces include standing forces, the Regular, Volunteer and Sponsored Reserves.
King Charles III, sovereign of the United Kingdom, is the commander-in-chief and is styled as Head of the Armed Forces,Forces Queen and Armed Forces , royal.uk., May 2023. Retrieved on 24 November 2023. with officers and personnel swearing allegiance to him. Long-standing constitutional convention, however, has vested de facto executive authority, by the exercise of royal prerogative, in the Prime Minister and the Secretary of State for Defence. The Prime Minister (acting with the Cabinet) makes the key decisions on the use of the armed forces.Governance of Britain, July 2007. Retrieved on 12 May 2013.Review of the Royal Prerogative Powers: Final Report, Ministry of Justice, October 2009. Retrieved on 12 May 2013. The UK Parliament approves the continued existence of the British Army by passing an Armed Forces Act at least once every five years, as required by the Bill of Rights 1689. Only a "standing army" requires reapproval by Parliament; the Royal Navy, Royal Air Force, and the Royal Marines, and any other forces are not included in the requirement. The armed forces are managed by the Defence Council.
The United Kingdom is one of five recognised nuclear powers, a permanent member of the United Nations Security Council, a founding and leading member of NATO and party to the AUKUS security pact and the Five Power Defence Arrangements. Overseas garrisons and training facilities are maintained at Ascension Island, Bahrain, Belize, Bermuda, British Indian Ocean Territory, Brunei, Canada, Cyprus, the Falkland Islands, Germany, Gibraltar, Kenya, Montserrat, Nepal, Qatar, Singapore and the United States. The British Armed Forces provided military training to approximately 140 countries in 2024–25.
History
Organisation With the Acts of Union 1707, the armed forces of England and Scotland were merged into the armed forces of the Kingdom of Great Britain.Acts of Union 1707 parliament. UK, accessed 31 December 2010; Uniting the kingdom? nationalarchives.gov.uk, accessed 31 December 2010; Making the Act of Union 1707 scottish.parliament.UK, accessed 31 December 2010
There were originally several naval and several military regular and reserve forces, although most of these were consolidated into the Royal Navy or the British Army during the 19th and 20th Centuries (the Royal Naval Air Service and Flying Corps of the British Army, by contrast, were separated from their parent forces in 1918 and amalgamated to form a new force, the Royal Air Force, which would have complete responsibility for naval, military and strategic aviation until the Second World War). Naval forces included the Royal Navy, the Waterguard, later renamed the HM Coastguard, and Sea Fencibles and River Fencibles formed as and when required for the duration of emergencies. The Merchant Navy and offshore fishing boat crews were also important manpower reserves for the armed naval forces. Any seaman was liable to impressment, with many so conscripted especially during the two decades of conflict from the French Revolution until the end of the Napoleonic Wars, and from 1835 registered on the Register of Seamen to identify them as a potential resource, and many of their seamen would serve part time in the Royal Navy Reserve, created under the Naval Reserve Act 1859, and Royal Naval Volunteer Reserve, created in 1903.
The British military (those parts of the British Armed Forces tasked with land warfare, as opposed to the naval forces) historically was divided into several military forces, of which the British Army (also referred to historically as the 'Regular Army' and the 'Regular Force') was only one.A LIST OF THE OFFICERS of the ARMY, (WITH AN ALPHABETICAL INDEX;) OF THE OFFICERS of the ROYAL ARTILLERY, THE ENGINEERS, the MARINE FORCES, AND OF THE OFFICERS on HALF-PAY; AND A SUCCESSION of COLONELS. THE THIRTY-SECOND EDITION. War Office. 31 March 1784 The oldest of these organisations was the Militia Force (also referred to as the Constitutional Force), which (in the Kingdom of England) was originally the main military defensive force (there otherwise were originally only royal bodyguards, including the Yeomen Warders and the Yeomen of the Guard, with armies raised only temporarily for expeditions overseas), made up of civilians embodied for annual training or emergencies, and had used various schemes of compulsory service during different periods of its long existence.
The Militia was originally an all infantry force, organised at the city or county level, and members were not required to serve outside of their recruitment area, although the area within which militia units in Britain could be posted was increased to anywhere in the Britain during the 18th century, and Militia coastal artillery, field artillery, and engineers units were introduced from the 1850s.The Militia Artillery 1852-1909, by Norman EH Litchfield. The Sherwood Press (Nottingham) Ltd. 1987 The Yeomanry was a mounted force that could be mobilised in times of war or emergency. Volunteer Force units were also frequently raised during wartime, which did not rely on compulsory service and hence attracted recruits keen to avoid the Militia. These were seen as a useful way to add to military strength economically during wartime, but otherwise as a drain on the Militia and so were not normally maintained in peacetime, although in Bermuda prominent propertied men were still appointed Captains of Forts, taking charge of maintaining and commanding fortified coastal artillery batteries and manned by volunteers (reinforced in wartime by embodied militiamen), defending the colony's coast from the 17th century to the 19th century (when all of the batteries were taken over by the regular Royal Artillery).Bermuda Forts 1612–1957, Dr. Edward Cecil Harris, The Bermuda Maritime Museum Press, Bulwark Of Empire: Bermuda's Fortified Naval Base 1860–1920, Lt.-Col. Roger Willock, USMC, The Bermuda Maritime Museum Press, The Bermuda Maritime Museum. The militia system was extended to several English (subsequently British) colonies, beginning with Virginia and Bermuda. In some colonies, Troops of Horse or other mounted units similar to the Yeomanry were also created. The militia and volunteer units of a colony were generally considered to be separate forces from the Home Militia Force and Volunteer Force in the United Kingdom, and from the militia forces and volunteer forces of other colonies. Where a colony had more than one militia or volunteer unit, they would be grouped as a militia or volunteer force for that colony, such as the Jamaica Volunteer Defence Force, which comprised the St. Andrew Rifle Corps, or Kingston Infantry Volunteers, the Jamaica Corps of Scouts, and the Jamaica Reserve Regiment,Jamaica Defence Force: Third Battalion Duties. Jamaica Defence Force website but not the Jamaica Militia Artillery. In smaller colonies with a single militia or volunteer unit, that single unit would still be considered to be listed within a force, or in some case might be named a force rather than a regiment or corps, such as is the case for the Falkland Islands Defence Force and the Royal Montserrat Defence Force. The militia, yeomanry, and volunteer forces collectively were known as the reserve forces, auxiliary forces, or local forces. Officers of these forces could not sit on courts-martial of regular forces personnel. The Mutiny Act did not apply to members of the Reserve Forces.