Wilson, Sir Henry Hughes (1864–1922), 1st baronet, soldier, and politician, was born 5 May 1864 at his family home at Currygrane, near Ballinalee, Co. Longford, the second son of four sons and three daughters of James Wilson, a landowner, and his wife, Constance Grace Martha Wilson (née Hughes), daughter of a Dublin lawyer. He was educated at home, and for three years (1877–80) in England at Marlborough College. He entered the army through the Longford militia, and in 1884 secured a commission in the Rifle Brigade. As a subaltern he served both at home and in India. In 1891 he married Cecil Mary Wray, daughter of the late George Gore Wray, land agent, and Charlotte Margaret Wray (née Waller). They had no children. Wilson attended the Staff College from 1891 to 1893, laying the foundation for a career as one of the most outstanding staff officers of his generation. During the Boer war (1899–1902), he excelled as brigade major of the 4th (light) brigade and was taken onto the staff of Lord Roberts (qv), C-in-C South Africa, who kept Wilson with him when he returned home to be C-in-C of the army. After a short period of regimental duty in 1902–3, Wilson returned to the War Office, where he worked on military education and staff duties. Here he formed part of a significant group of officers who both pressed for and helped to implement the army reforms introduced after the Boer war by Richard Haldane, secretary for war (1905–12).
In 1907 Wilson was appointed commandant of the Staff College with the rank of brigadier-general. He was a notably successful commandant, with a real talent for teaching: enthusiastic, inspiring, and with a particular flair for lecturing, when his ready wit came into play. Beyond the classroom he also led by example in the outdoor activities, including ‘staff rides’, sports, and games. Superbly fit in his early forties – he was a rangy 6 feet 4 inches tall and about 12 stone in weight – he could outrun men half his age. He stressed practical exercises and took the students on battlefield tours of France and Belgium. He also spent much of his spare time over the next few years exploring the Franco–Belgian frontier with Germany, walking and cycling over the territory he foresaw would be fought over in the war that he believed was inevitable between Germany and France. A passionate Francophile, he increasingly conceived his role as being to prepare the British army to take its place at the side of the French, an attitude reinforced by his close friendship with the French general Ferdinand Foch, whom he first met when Foch was commandant of the French staff college.
Wilson returned to the War Office in 1910 to become director of military operations (DMO), which enabled him to put practical military flesh on the diplomatic bones of the entente cordiale with France. Over his four years as DMO, especially after he had secured the explicit political approval of the committee of imperial defence in August 1911, he and his staff worked assiduously to perfect what became known as the ‘W-F’ (‘with France’) plan, which provided for the mobilisation of a British expeditionary force (BEF) and its deployment across the channel to support the French against a German invasion. It was substantially owing to Wilson's efforts that the small British professional army in 1914 was better prepared for war than it had ever been. While at the War Office, Wilson, who was promoted major-general in November 1913, began to get caught up in political matters. He enthusiastically supported the campaign (headed by Lord Roberts) for national service in Britain, believing it to be a social good, as well as a military necessity in the face of a growing challenge from imperial Germany.
But his principal political concern throughout his life was with the union between Great Britain and Ireland. This was characteristic of his background in the middling class of protestant Irish landowners, and was reinforced by Ulster forebears on his father's side. The Wilson family took part in the political organisation of Irish unionism in the later nineteenth century. Wilson's father was an active member of the Irish Landowners' Convention, and he and James MacKay Wilson (Wilson's elder brother) were prominent in the Irish unionist alliance. In 1913, when Ulster unionists had begun to organise armed opposition to the threat of home rule, Lord Roberts, who had been asked to take command of the UVF, suggested that Wilson might become his chief of staff. The following year, throughout the crisis precipitated by the Curragh incident, when sixty cavalry officers resigned their commissions rather than accept orders that they thought were intended to coerce Ulster into an all-Ireland parliament, Wilson worked behind the scenes in support of the Ulster cause, and kept leading British opposition politicians informed of developments. While his behaviour enhanced his standing among conservatives and unionists, it made him extremely suspect in the eyes of many Liberals, including the prime minister, Herbert Asquith. Among some army colleagues, too, Wilson was gaining a not wholly undeserved reputation as a ‘political’ soldier with a penchant for ‘intrigue’ and ‘mischief-making’.
After war with Germany was declared in August 1914, and the decision taken to commit the BEF to support the right flank of the French army, Wilson's careful work as DMO was fully vindicated. In the eyes of some, the deployment of the BEF, modest in size though it was, was sufficient to tip the balance of military strength in favour of the French and British, thus spiking German plans for a quick victory in the west. Wilson went to France with the BEF as sub-chief of the general staff. At the end of 1914 Sir John French (qv), C-in-C of the BEF, wanted to promote Wilson to be chief of staff, but this was blocked by Asquith and Lord Kitchener (qv), the secretary for war; their antipathy to Wilson was shared by French's successor, Sir Douglas Haig, and Wilson was kept out of really important jobs for much of the war. In 1915–16 Wilson served successively as chief liaison officer to the French headquarters (a job for which he was well qualified, but not one which fully utilised his abilities), and in command of IV Corps, a formation which saw little action under his command. He was knighted in 1915.
Wilson's fortunes rose after David Lloyd George, who had respected Wilson's strategic vision before the war, became prime minister in December 1916. Lloyd George was frustrated by the continual, costly war of attrition along the western front, and the apparent inability of the British military high command to secure success against the enemy. He found both Sir Douglas Haig and Sir William Robertson, the chief of the imperial general staff (CIGS) and the government's principal military adviser, unsympathetic characters. By contrast, he was attracted by Wilson's gregarious sociability, nimble intelligence, and lucid ability to explain military situations to civilians in a comprehensible fashion. Following a trip to Russia in a high-powered (though, as it turned out, futile) mission to bolster a failing ally, and a further period in Franco–British liaison, Wilson was appointed in September 1917 to head the not-very-onerous domestic eastern command. Based in London, he was increasingly used by Lloyd George as an unofficial sounding-board for military and strategic matters. In February 1918 Lloyd George manœuvred Robertson out of the CIGS-ship and replaced him with Wilson, who remained at the centre of British war policy-making for the rest of the war. In a period of ‘total’ war, moreover, and within a generally democratic political context, Wilson provided the crucial and effective link between the civil and military components of the British war effort, which his predecessors as CIGS had failed to do.
Wilson, who was promoted field marshal in July 1919 and created a baronet the following month, remained CIGS until February 1922. In peacetime circumstances, however, when domestic and foreign policy issues came to the fore, his value as a government adviser declined. Wilson, for all his political instincts, was not a man much given to compromise, upon which ‘the art of the possible’ depends. Faced with an over-extended empire in the aftermath of the war, and an upsurge of internal unrest, all Wilson could advise was a blunt ‘govern or get out’ approach. He was especially intransigent regarding Ireland, where he unremittingly advocated a stern policy of repression to counter the violent nationalist challenge of 1919–21. He was shocked and appalled by Lloyd George's pusillanimous covert encouragement of irregular counter-terror led by the ‘Black and Tans’ and Auxiliaries. Vainly he proposed a fully militarised offensive against the IRA, with the government taking open responsibility for formalised reprisals and collective punishments. Politically this was never a realistic option, and when Lloyd George opened negotiations with de Valera (qv) in the summer of 1921 Wilson refused to speak to the prime minister again.
During the war, when he felt that the nation was not properly utilising his manifold talents, Wilson toyed with the idea of entering parliament. After he retired as CIGS in 1922 he finally accepted an Ulster unionist offer of a seat, and was elected unopposed for the United Kingdom constituency of North Down. He was also taken on as chief security adviser to the Northern Ireland government, where his wise but uncongenial advice that security in the province should be taken out of the hands of local, part-time, quasi-military police, and placed in the safer, nonsectarian hands of the army was never acted upon. On 22 June 1922 he was assassinated on his doorstep in London by two members of the IRA, both of whom had served in the British army during the first world war, one losing a leg. Although there was (and has been) much speculation about who gave the order for the killing, it was probably a purely local, London initiative. At the time, nevertheless, suspicion fell on the anti-treaty republicans, and powerfully intensified British pressure on the provisional government to cease tolerating the occupation by Rory O'Connor (qv) of the Four Courts in Dublin. British outrage at Wilson's killing was undoubtedly one factor in Dublin's decision to attack O'Connor, which in turn helped to precipitate the civil war of 1922–3.
There are portraits of Wilson by William Orpen (qv) (1919, National Portrait Gallery, London), Oswald Birley (1922, Marlborough College; a copy of this painting hung for many years in what was known as the ‘prime minister's room’ in Parliament Buildings, Stormont, Belfast), and John Singer Sargent (1922, as part of the group portrait Some general officers of the great war, National Portrait Gallery, London). His diaries and papers are preserved in the Imperial War Museum, London.