Key facts about the Battle of the Somme

The Battle of the Somme was one of the most bitterly contested and costly battles of the First World War, lasting nearly five months. While the the first day of the battle is most remembered, the Somme became a battle of attrition, where each side sought to wear the other out. 

On 15 September, tanks were used for the first time with some success, but they did not bring a breakthrough any closer. Operations on the River Ancre continued with some gains, but in deteriorating weather conditions major operations on the Somme ended on 18 November. 

Over the course of the battle, British forces took a strip of territory 6 miles (10km) deep by 20 miles (32km) long.

The Battle of the Somme inflicted heavy casualties on both sides. 

The first day on 1 July 1916, was one of the most devastating. British Troops went 'over the top' after a week-long artillery bombardment of the German lines and found that the German defences had not been destroyed as expected. Many units suffered very high casualties with little progress.

By the end of the first day British forces had suffered 57,470 casualties, of whom 19,240 were killed. This represented the largest losses suffered by the British Army in a single day. 

While casualty rates were not as high for the rest of the campaign, they were consistently heavy. Both sides fought intensively for every yard of ground within a relatively small geographical area.

In total over a million men from both sides – including Britain and her Empire forces, France and Germany – became casualties during the battle.

Many men who had volunteered for Army service in 1914 and 1915, first saw combat on the Somme. This included men who had joined Pals battalions – infantry units that were made up of friends, relatives and workmates from the same communities.

After around a year of training, most of these men began to see active service from late 1915 and early 1916, particularly on the Western Front. As a result, the Battle of the Somme, the largest offensive the British Army had launched to date, was the first to be fought by a largely citizen army made up of civilian volunteers rather than professional soldiers.

Many of the attacking British infantry did not have battlefield experience. As one French officer wrote on 10 July 1916, 'The British...infantry... is very brave but undergoing a costly apprenticeship'.

Although the British Army suffered heavy casualties for relatively little territorial gain on the Somme, the battle provided important experience for troop. The British Army developed tactics and gained experience that later contributed to victory on the Western Front. 

Over the nearly five months of fighting on the Somme, the inexperienced citizen army began to evolve into a battle-hardened one. The same was also true of British commanders, who had never previously commanded troops on this scale before. Improvements were made in the use of artillery and infantry tactics, and new weapons, including tanks, began to be integrated in the British Army's methods. 

While this came at a very high cost in casualties, it proved equally costly for the German Army, which began to realise that the British Army was becoming a major opponent.