In the early days of the First World War on 5 August 1914, Monro was deployed to France as General Officer Commanding 2nd Division, which played an important part in the First Battle of Ypres.[1][17] He led with what a subordinate described as "the gift of personal magnetism".[18] On 27 December 1914 he became General Officer Commanding I Corps, with the temporary rank of lieutenant-general.[19] He was made General Officer Commanding Third Army on 15 July 1915 with the temporary rank of general.[1][20] He was promoted to the permanent rank of lieutenant-general on 28 October.[21]
In October 1915, the seventh month of the Gallipoli campaign, General Sir Ian Hamilton was dismissed as Commander-in-Chief of the Mediterranean Expeditionary Force. Charles Monro was sent to evaluate what had been achieved and to recommend the next steps for the campaign.[22] The Allied position had been drastically altered by the entry of Bulgaria into the war and the Central Powers' subsequent swift conquest of Serbia, which opened the railway from Germany to Constantinople for transporting heavy guns and ammunition.[23] After three days conferring and inspecting the three beachheads, Monro cabled Secretary of State for War Herbert Kitchener to recommend evacuating "the mere fringe of the coast-line" that had been secured.[24] Kitchener would not authorize a withdrawal, which was strongly opposed by the Navy, instead, he came to the Middle East to see for himself. After arriving on 9 November 1915 he and Monro toured the fronts, landing on open beaches since there were no ports. Then they visited the Allied lines in Greek Macedonia, where reinforcements were badly needed. On 17 November 1915 Kitchener agreed to evacuate and put Monro in control as Commander-in-Chief Mediterranean. The architect of the Dardanelles campaign, Winston Churchill, resigned from the government in protest. He later memorably described Monro's stance as "He came, he saw, he capitulated" (a parody of Julius Caesar's line veni, vidi, vici).[25] The War Committee dithered, finally on 7 December agreeing to evacuate two of the bridgeheads (ANZAC Cove and Suvla Bay). Their reluctance was understandable: Ottoman guns were able to strike the landing zones on all three beachheads, so evacuation casualties were estimated at thirty to forty per cent — Monro requested fifty-six hospital ships. On 19–20 December the two beachheads were evacuated without a single casualty, leaving behind only some spiked artillery and slaughtered mules. It was a masterly display by the commanders of the beachheads and their staff. After further pressure from Monro, the evacuation of the remaining beachhead at Cape Helles was authorized on 28 December with the agreement of the French who had troops there. It was skillfully executed on the night of 8–9 January 1916, again astonishingly without casualties. They had taken off 83,048 men, 4,695 horses and mules, 1,718 vehicles, and 186 heavy guns.[26]
In 1916 Monro commanded the British First Army in France before becoming Commander-in-Chief India later that year.[1] He was a fine choice, because his "Standard was whether a man was an Empire-builder."[27] One of his responsibilities was the campaign in Mesopotamia. On 1 August 1916 the Chief of the Imperial General Staff (CIGS), General Sir William Robertson, ordered him to "keep up a good show" in Mesopotamia but not to make any further attempts to take Baghdad — this restriction was overruled on the War Committee by Curzon and Chamberlain. On his way to India Monro inspected the forces in Mesopotamia commanded by General Maude. After receiving Monro's favourable report on 18 September 1916 the War Committee authorized Maude to attack.[28] On 1 October 1916, Monro was promoted to the substantive rank of general.[29] Baghdad was taken on 11 March 1917. In off hours Monro continued to charm with his "whimsical, almost fantastic type of humour."[30]
Later life
In May 1921, Monro was created a Baronet, of Bearcrofts in the Shire of Stirling.[31] In 1923 Monro was appointed Governor of Gibraltar.[1]