Curragh incident in the context of Sir Henry Wilson, 1st Baronet

The Home Rule Crisis was a political and military crisis in the United Kingdom of Great Britain and Ireland that followed the introduction of the Third Home Rule Bill in the House of Commons of the United Kingdom in 1912.

Unionists in Ulster determined to prevent any measure of home rule for Ireland and formed a paramilitary force, the Ulster Volunteers, which threatened to resist by force of arms the implementation of the Act and the authority of any Dublin Parliament. Irish nationalists responded by setting up the Irish Volunteers "to secure the rights and liberties common to all the people of Ireland". Both sides then began importing weapons and ammunition from Germany, in the Larne gun-running and Howth gun-running incidents. HM Government's ability to face down unionist defiance was thrown into question by the "Curragh incident", when dozens of British Army officers threatened to resign or face dismissal rather than deploy into Ulster (ostensibly to secure arms against Ulster loyalist seizure), forcing a climb-down by the government. The crisis was temporarily averted by the outbreak of World War I. The Home Rule Bill was enacted, but its implementation was suspended for the duration of the war.

Field Marshal John Denton Pinkstone French, 1st Earl of Ypres, KP, GCB, OM, GCVO, KCMG, PC, PC (Ire) (28 September 1852 – 22 May 1925), known as Sir John French from 1901 to 1916, and as The Viscount French between 1916 and 1922, was a senior British Army officer.

Born in Kent, he saw brief service as a midshipman in the Royal Navy, before becoming a cavalry officer. He achieved rapid promotion and distinguished himself on the Gordon Relief Expedition. He became a national hero during the Second Boer War. He commanded I Corps at Aldershot, then served as Inspector-General of the Forces, before becoming Chief of the Imperial General Staff (CIGS, the professional head of the British Army) in 1912. He helped to prepare the British Army for a possible European war, and was among those who insisted that cavalry still be trained to charge with sabre and lance. During the Curragh incident he had to resign as CIGS.

The history of the British Army spans over three and a half centuries since its founding in 1660 and involves numerous European wars, colonial wars and world wars. From the late 17th century until the mid-20th century, the United Kingdom was the greatest economic and imperial power in the world, and although this dominance was principally achieved through the strength of the Royal Navy (RN), the British Army played a significant role.

As of 2015, there were 92,000 professionals in the regular army (including 2,700 Gurkhas) and 20,480 Volunteer Reserves. Britain has generally maintained only a small regular army during peacetime, expanding this as required in time of war, due to Britain's traditional role as a sea power. Since the suppression of Jacobitism in 1745, the British Army has played little role in British domestic politics (except for the Curragh incident), and, apart from Ireland, has seldom been deployed against internal threats to authority (one notorious exception being the Peterloo Massacre).