The Battle of the Somme (1 July–18 November 1916) was a joint British-French action to break the stalemate on the western front and achieve a decisive victory. Following a successful recruiting campaign in Britain, which resulted in the formation of many ‘Pals’ Battalions’ made up of groups of men who were friends, relations and colleagues drawn from the same community, the Battle of the Somme was the first major action of the Great War in which Britain’s new volunteer army took a leading role. A seven-day artillery bombardment, begun on 24 June, was the prelude to the battle, intended to devastate the German defenders on the upper reaches of the River Somme in northern France. However, the British artillery was too thinly spaced to create an impenetrable barrage of fire and many of the shells failed to explode. The first day of the Battle of Somme cost 57,520 British casualties, making it the bloodiest day in British military history. The British were bogged down, the French were still heavily engaged at Verdun, and a period of deadlock ensued, punctuated by attritional fighting, which sacrificed many lives for minimal gains. In mid-September, the British introduced the tank, a totally new weapon. Despite the alarm, these caused the Germans, the British advance stalled. The final act of the Somme offensive took place between 13–18 November. The British had inched forward to the River Ancre and used a combination of tanks, creeping artillery barrage and infantry to neutralize the Germans in their dugouts. The artillery barrage inched forward in small increments, every few minutes, with fire passing from one line to the next. This shielded the infantry who advanced 50 yards behind. The tanks were only being deployed for the second time and were used to ‘mop up’ after the infantry. In the final engagement of the campaign, the Canadian 1–3 Divisions, who had earlier been repeatedly repulsed in their efforts to take the Germans’ Regina Trench, surged forward to capture Desire Trench. The onset of winter called a close to the battle where an advance of 6 miles (10 km) incurred 650,000 Allied casualties and lost lives.