Today marks the 100-year anniversary of the Battle of the Somme.
With more than 19,000 soldiers killed, it is the bloodiest day in British military history.
Here’s all you need to know...
What led up to the Battle of the Somme?
The Battle of the Somme was a joint operation between British and French forces intended to relieve pressure on the French who were engaged with German forces at Verdun and achieve a decisive victory over the Germans on the Western Front.
In December 1915, Allied commanders had met to discuss strategies for the upcoming year and agreed to launch a joint French and British attack in the region of the River Somme in the summer of 1916.
Intense German pressure on the French at Verdun throughout 1916 made action on the Somme increasingly urgent and meant the British would take on the main role in the offensive.
They were faced with German defences that had been carefully laid out over many months.
Despite a seven-day bombardment, prior to the attack on 1 July, the British did not achieve the quick breakthrough their military leadership had planned for and the Somme became a deadlocked battle of attrition.
What was achieved?
Very little. Over the next 141 days, the British advanced a maximum of seven miles.
More than one million men from all sides were killed, wounded or captured.
British casualties on the first day – numbering over 57,000, of which 19,240 were killed – make it the bloodiest day in British military history.
While synonymous with trench warfare, the Somme Offensive was a battle that took place at a time where the established schools of thought regarding warfare were being proven to be hopelessly outdated.
September 14 marked the first sustained use of tanks in a major battle by the British and began a period of success for the British at the Somme. Ultimately bad weather meant the use of tanks was abandoned as winter set in.
The role of airpower in modern warfare began to change during the Somme as well. Allied air superiority proved vital and air reconnaissance was crucial in planning actions.
The Somme, like Verdun for the French, has a prominent place in British history and popular memory and has come to represent the loss and apparent futility of the war.
But the Allied offensive on the Somme was a strategic necessity fought to meet the needs of an international alliance.
British commanders learned difficult but important lessons that would contribute to eventual Allied victory in 1918.