On July 1, 1916, the first day of the Battle of the Somme, twenty thousand soldiers of the British Army are killed and forty thousand are wounded. The 36th (Ulster) Division suffers heavy casualties.

The Battle of the Somme, also known as the Somme Offensive, is a battle of the World War I fought by the armies of the British and French empires against the German Empire. It takes place between July 1 and November 18, 1916 on both sides of the upper reaches of the River Somme in France. The battle is intended to hasten a victory for the Allies and is the largest battle of World War I on the Western Front. More than 3 million men fight in this battle and one million men are wounded or killed, making it one of the bloodiest battles in human history.

The French and British commit themselves to an offensive on the Somme during Allied discussions at Chantilly, Oise, in December 1915. The Allies agree upon a strategy of combined offensives against the Central Powers in 1916, by the French, Russian, British and Italian armies, with the Somme offensive as the Franco-British contribution. Initial plans call for the French army to undertake the main part of the Somme offensive, supported on the northern flank by the Fourth Army of the British Expeditionary Force (BEF). When the Imperial German Army begins the Battle of Verdun on the Meuse on February 21, 1916, French commanders divert many of the divisions intended for the Somme and the “supporting” attack by the British becomes the principal effort.

The first day on the Somme, July 1, sees a serious defeat for the German Second Army, which is forced out of its first position by the French Sixth Army, from Foucaucourt-en-Santerre south of the Somme to Maricourt on the north bank and by the Fourth Army from Maricourt to the vicinity of the Albert–Bapaume road. The first day on the Somme is, in terms of casualties, also the worst day in the history of the British army, which suffers 57,470 casualties. These occur mainly on the front between the Albert–Bapaume road and Gommecourt, where the attack is defeated and few British troops reach the German front line. The British troops on the Somme comprise a mixture of the remains of the pre-war standing army, the Territorial Force, and Kitchener’s Army, a force of volunteer recruits including many Pals Battalions, recruited from the same places and occupations.

The battle is notable for the importance of air power and the first use of the tank. At the end of the battle, British and French forces have penetrated 6 miles into German-occupied territory, taking more ground than in any of their offensives since the First Battle of the Marne in 1914. The Anglo-French armies fail to capture Péronne and halt three miles from Bapaume, where the German armies maintain their positions over the winter. British attacks in the Ancre valley resume in January 1917 and force the Germans into local withdrawals to reserve lines in February, before the scheduled retirement to the Siegfriedstellung (Hindenburg Line) begins in March.

Debate continues over the necessity, significance and effect of the battle. David Frum opines that a century later, “‘the Somme’ remains the most harrowing place-name” in the history of the British Commonwealth.